Starting from the entrance gate, the first visible building is the Greek Theater (Teatro Greco) (n. 1), with its great semicircular cavea and the adjacent vast rectangular square, leaning on substructures.
Ligorio made some excavations in this building, finding some herms, while in the XVIII century

The Casino del Fontanile was built over the ruins of a double Cryptoporticus underneath the Palestra, visible in the lower floor.

count Fede found two herms, one of the Tragedy the other of the Comedy. In recent times, the Greek Theatre has been cleaned up, the cavea is again visible while the rectangular square still is covered by dirt. The plans drawn by Contini and Piranesi also show a Latin Theater - which supposedly was near the Palestra, but no trace has ever been found of it.
Very close to the Greek Theater, is another complex traditionally known as the Palestra (n. 2): according to Ligorio's description, it had three great squares, one of which was paved with cipollino marble. Recent excavations carried out by the Soprintendenza Archeologica del Lazio have confirmed Ligorio's description, finding a large rectangular open court, paved with large slabs of cipollino marble. The court was surrounded by a double porch with opus sectile pavements, one featuring tridimensional cubes, the other with rectangles in herringbone pattern. The open court and its two porticoes leaned over a great substructure, consisting of a double cryptoporticus.

One of the corridors of the double Cryptoporticus which formed the substructures of the Palestra.

It is fairly well preserved because it is still used for storage, and was partly enclosed in the Casale del Fontanile (also known as the Fontanile di Palazzo). Its name hints to a source that still exists and flows, and probably supplied the waterworks of this lower part of the Villa.

In the same area of the Palestra, another Casale was built in the XVIII century by count Fede, enclosing some roman ruins under it. In its lower floor are still visible some stucco vaults, recently studied by professor Mariette de Vos and the University of Trento. Near this Casale are other roman ruins, now used for storage and cars; here too are preserved some stucco vaults, but the greater part of the structure is still underground.

A stucco vault preserved in a Casale of the XVIII century, built over the ruins of the Palestra.

The Palestra is one of the less known buildings of the Villa; excavations date back to the XVIII century and the most reliable plans are still those by Contini and Piranesi. Luigi Canina (Canina 1856) is the only one who published a plan of the open court with its double porch, while the plans by Contini, Piranesi and Salza Prina Ricotti just show the lower floor with double cryptoporticus.

The circular temple dedicated to the Venus of Cnidos stood over an artificial terrace, where in 1704 Count Fede built his Casino (visible on the right).

A long alley flanked by century-old monumental cypressus trees, which probably followed the line of an ancient access road, climbs up to a higher level, passing nearby the Casino Fede. It was built in 1704 over the ruins of a Nymphaeum (n. 3) with a round doric temple dedicated to the Venus of Cnido; underneath this building has been uncovered an ancient paved road, partly runnig in a tufa tunnel.
This Nymphaeum is partially shown in the plans by Contini and Piranesi, and was restored several times. It was built over an artificial terrace whose containment wall in opus incertum was inherited from the previous republican villa, later enclosed in the hadrianic buildings of the Imperial Palace (n. 12). The opus incertum containment wall was restored in the 1990's.
The terrace overlooked the panorama on the east side, and at its center was the doric round temple, surrounded by a curved porch with two side apses; at its center there probably was the main access to the area. The northern part of the building has been enclosed by the Casino Fede. All the buildings and Casali built by and belonging to Count Fede are shown in a XVIII century map of his properties (Ristori Gabbrielli 1770).

The long alley flanked by cypressus trees, which probably follows the ancient access road to the Pecile.

A second alley flanked by cypressus trees goes up until it reaches a long tufa and brick wall, belonging to the Pecile (n. 16): its double porch was conceived to allow people to stroll in the shade or in the sunshine, depending on season and temperature, and to reach the lenght of a mile after a certain number of rounds. The double porch was built at the beginnings of Hadrian's reign, in year 117 A.D., as shown by brick stamps.

The long wall of the porticus of the Pecile. The 104 holes on its top were meant for the beams of the roof. In this porch it was possible to stroll on the sunny or the shaded side, or in the warmer or cooler side, according to seasons.

West of the double porch is the vast eplanade of the Pecile, decorated by a large water basin at its center, surrounded by another porch. The artificial esplanade rests on a vast substructure, called Cento Camerelle or Hundred Chambers. The brick stamps found in this part of the Pecile date back to the years 123-124 A.D., showing that it was completed later, after finishing the substructures which surely requested a much longer period of time.

The great substructures of the Cento Camerelle supported the artificial esplanade of the Pecile; there lived the servants of the Villa, from slaves to soldiers, with separated access roads. A double wall isolated the rooms from humidity.

The Hundred Chambers consisted of dozens of rooms, housing the servants and the soldiers of the Villa, with no direct link to the upper level of the Pecile. To protect the rooms from humidity, there was an hollow space between their rear wall and the hill; they served as substructure also for the terrace that linked the Pecile to the Vestibulum (n. 25).

On the Jubilee of year 2000, the main access to the Villa has been re-excavated. On the left are the Cento Camerelle with their service road. Further right is a paved road in the shape of a great ring, and in the background is visible the monumental staircase going up to the Vestibulum.

In the Jubilee year 2000, the Soprintendenza Archeologica del Lazio uncovered a vast area near the Hundred Chambers, finding a double road system. A first paved road, quite narrow, flanked the Hundred Chambers, reaching a net of subterranean cryptoporticoes underneath the Vestibulum and the Great and Small Baths. An high wall separated this road from the second one, which was the main access to the Villa. It is a wide rectangular ring, paved in stone, which reached the monumental staircase leading to the Vestibulum entrance (n. 25) (see Rinaldi 2000 and Mari 2001). On the small hill east of the paved ring were also discovered the foundations of a building which has been ipotetically identified as a sacellum dedicated to Antinous, the emperor's lover.

The majestic Philosophers' Hall was the place where the Emperor officially received. Completely reveted with precious marbles, had niches decorated with statues, some of which were found nearby in the Cento Camerelle.

On the southern side of the Pecile two arched stairways climbed up to the Philosopher's Hall (Sala dei Filosofi) (n. 17). It is a vast rectangular hall with a great apse, which was built together with the Maritime Theater; its main access with two columns is on the northern side. A subterranean secret corridor linked it with the Garden Stadium and the Pecile.
This probably was the monumental audience hall for the Emperor. Ligorio wrote that it was lavishly decorated with precious marbles, and traces are still visbile on the walls. The niches were meant for statues, possibly those found by Michilli in the nearby Cento Camerelle.
Adjacent to the Sala dei Filosofi is the so-called Maritime Theatre or Teatro Marittimo (n. 18), one of the most outstanding buildings of the Villa. Its main access was on the

The "Maritime Theater" (Teatro Marittimo) is one of the most outstanding buildings of the Villa. Surrounded by a circular water basin, had a small island at its center, accessible with two removable bridges. There the Emperor could rest in total safety and absolute privacy.

northern side, on a terrace, with a little staircase used by people coming from the Pecile or from the area in front of the Philosopher's Hall. This access path was completely separated from the one leading to the Greek and Latin Libraries, but the three building all belonged to the private part of the Villa, and therefore their entrance was hidden and concealed. On the outside, the Maritime Theater had the same shape and measurements of the Pantheon in Rome, a great circular building with a columned porch in front. Inside, however, the arrangement was completely different: there was a circular porch surrounding a water channel in the shape of a ring and, at its center, a small artificial isle, housing a miniature villa with all comforts. There was a small atrium-garden, a triclinium (dining room) flanked by two small halls; on the eastern side were cubicula for sleeping. On the western side there was a little Therma with a water basin, heated rooms and latrinae. The island was connected to the porch by two removable bridges, which secured privacy and safety to the Emperor; in late antique times they were replaced by a masonry bridge.
The pavements were in opus sectile in the island and in mosaic in the inner porch; the walls still have traces of the marble revetment. The colums supported an architrave decorated by a marble frieze with sea monsters (some fragments are still visible in situ). The plan of the Maritime Theatre, also called Natatorio, was first drawn by Andrea Palladio, is visible in all ancient maps, since the building has fascinated all Renaissance architects. In the 1980's was thoroughly studied and published in an excellent book by Ueblacker (Ueblacker 1985).

The great dome of the Thermae with Heliocaminus covered an intensely heated hall.

Between the Maritime Theatre and the Pecile are the so called Terme con Heliocaminus (n. 19), whose name comes from the great dome that covered an intensely heated room, a circular sudatio. Published in the 1970's by Verduchi (Verduchi 1975), the building was modified and restored several times. Recent articles by Manderscheid assume that the great circular hall had a water basin heated with a 'samovar' system - a bronze immersion brazier (Manderscheid 2000). There also was a frigidarium paved with cipollino marble, featuring a pool for cold water, and a series of lightly heated rooms, some of which were used as apodyteria (dressing roms). The Terme con Heliocaminus served the surrounding eastern buildings of the Villa, from the Greek and Latin Libraries to the Imperial Palace.

East of the Maritime Theatre is a series of buildings connected one with the other. Starting from north is the Lower Library Terrace (Terrazza inferiore delle Biblioteche) (n. 5), with a a containment wall on its southern end, decorated by niches for statues.

The Greek Library together with the Latin Library formed a monumental access to the quarters of the Imperial Palace.

The Latin Library with its great apsed hall.

The tipically concealed access consisted of two small staircases leading up to the Upper Library Terrace and to the so-called Greek and Latin Libraries (Biblioteca Greca and Biblioteca Latina) (n. 9-10). In front of them there was a long fountain with octagonal basins at the sides. The two Libraries were a sort of scenographic and monumental wing preceding the private quarters of the Villa.
The Greek Library (Biblioteca Greca) (n. 10) had two great squared halls, one following the other, decorated by rectangular alcoves; great openings allowed an axial see-through from the entrance to the internal hall. In its south-eastern side a series of irregularly shaped rooms linked the Greek Library to the Libraries Courtyard (n. 11), which had a different alignment.
The Greek Library still has an upper floor with heating system, and was probably used as winter residence before the construction of the Winter Palace (n. 22), which also had a winter heating system.
The Latin Library (n. 9) had two similar halls decorated by alcoves, with a dominance of curved shapes. The internal apse of the second hall was visible from the entrance; a series of rooms linked the different alignments of the Library and of the Library Courtyard (n. 11).
The two Libraries, lavishly decorated with precious marbles on walls and pavements, had the shape of two towers, and flanked an ancient republican Nymphaeum. Here too there was no direct access, just two small and concealed corridors flanking the Nymphaeum and leading into the Libraries Courtyard (Cortile delle Biblioteche) (n. 11).

The Cryptoporticus with Mosaic Vault, inherited from the ancient republican Villa and preserved by the hadrianic structures, in an XIX century engraving by Penna.

Formerly, this was the garden of the republican villa, enclosed by the building of the Imperial Palace (n. 12), a vast rectangular area surrounded by porticoes and paved with opus sectile. On its north-western side, along which also are the Greek and Latin Libraries, was the Nymphaeum previously mentioned, covered by a barrel vault, with an apse decorated by niches for statues and fountains; it had a cistern over its roof, supplying the waterworks.
The old republican Villa originally rested upon a basis villae, which was a masonry podium formed by a cyptoporticus with four aisles, called the Mosaic Vault Cryptoporticus (Criptoportico con Volta a Mosaico) (n. 13). In the ceiling of one of its corridors is still visible a wonderful mosaic made of glass tesserae and shells, with a decoration of flowers and birds. The cryptoporticus was linked to other subterranean galleries, partly unexcavated, substructing the area over which is the Imperial Palace (n. 12).

The mosaic pavements of the Hospitalia employ a new repertoire of stylized vegetal drawings, together with traditional geometric patterns.

On a lower level - and in a more secluded location - is another complex formed by the Imperial Triclinium (Triclinio Imperiale) (n. 7) and the Hospitalia (n. 8). The Hospitalia were decorated by beautyful black and white mosaics with vegetal arabesque drawings, tipical of the hadrianic age. It had ten T shaped cubicula whose niches served for the beds of its guests. The pavement hidden by the beds had simple drawings, while the central and visible part of the floor had highly decorative patterns. There also was a central hall with a base for a statue, possibly a sacellum.

In the Imperial Triclinium is still visible this vaulted cryptoporticus, engraved by Piranesi.

The Imperial Triclinium (Triclinio Imperiale) (n. 7) is on a lower level, and was linked to the Hospitalia by two staircases, a main and a secundary one. On its southern side is still visible a Cryptoporticus with rampant vault engraved by Piranesi; there are surviving parts of the frescoes and signatures of ancient visitors. On the opposite side of the building, a great halled opened with two colums on a small garden; it was flanked by two corridors on which opened several cubicula. The mosaics had simple black borders, showing that this, together with the Hospitalia, was a secundary building for high ranking personnel, in a defiladed location, with multiple latrinae (on this complex see De Franceschini 1991, p. 374-376).

This hall in the Imperial Palace was a miniature Library with shelves.

Further south is the Imperial Palace (Palazzo Imperiale) (n. 12), with many different rooms. It is not possible to understand meaning and function of each of them, but has been identified a small Library with niches for the papyri, a Summer Triclinium (Triclinio Estivo) with a half-dome decorated by niches – one of the many scattered in the Villa.
The core of the building was a rectangular court surrounded by porticoes, originally belonging to the old republican Villa, flanked by a series of cubicula on the eastern side.

The Summer Triclinium of the Imperial Palace, one of the many dining halls scattered throughout the Villa.

South of the porch was a great Nymphaeum with semicircular water staircases, from which the water was flowing into a rectangular basin painted in light blue. In this part of the Villa are preserved some ancient mosaic pavements of republican age and other opus sectile or mosaic pavements of hadrianic age. In the area of the so-called Triclinium of the Centaurs, during the XVIII century, Cardinal Marefoschi found several precious mosaic panels (vermiculata) representing idyllic landscapes, scenic masks or beasts linked to the dionysiac iconography. They are now in the Vatican Museums of Rome or in Berlin.
(About the republican villa enclosed in the hadrianic buildings see Lugli 1927 and De Franceschini 1991 p. 414).

The Hall with Doric Pillars was located between the Piazza d'Oro, the Imperial Palace and the Winter Palace (Edificio con Peschiera), linking them together.

Behind the Nymphaeum, another cryptoporticus gave acces to the Building with Doric Pillars (Edificio con Pilastri Dorici) (n. 14), with a rectangular porch and an apsed hall decorated by a statue on its western side. Little is known about this building, which has been excavated several times and restored in 1966, rebuilding the pillars and part of the vault of the porch. Some scholars believe it was a royal throne hall because of its apse. But since the apse actually was an open air garden, the building's main funcion was to link the Imperial Palace to the area south of it, between Piazza d'Oro (n. 15) and the Winter Palace (n. 22), which has never been explored thoroughly.

The great substructures of the Tempe Pavilion looked like a powerful tower. The door in its lower floor gives access to the so-called Stallone.

The eastern part of the Villa was perched over the Tempe Terrace (Terrazza di Tempe) (n. 4), a vast esplanade buttressed by powerful containment walls, which look like the walls of a fortress (see picture in the Architecture and image section of this site).

The Stallone in the Tempe Pavilion. Its ceiling still has the original revetement of fake stalactites ('tartari'), incredibly well preserved, and underneath a rocaille simulating a Grotto.

The Tempe Terrace started from the Ninfeo Fede and reached south to a sort of tower, on top of which was the Tempe Pavilion (Padiglione di Tempe) (n. 6).
This powerful tower linked different levels: in the lower one still survives a vast hall, the so-called Stallone, an artificial and 'virtual' grotto, completely reveted by 'tartari' or pseudo-grotto, imitating stalactites. Here was found a statue of Heracles, hinting to the Afterworld, and also to the sancuary of Ercole Vincitore (Winning Heracles) in the nearby town of Tivoli. From the Terrace of Tempe a ramp and a staircase lead up to the upper floor, where was the Tempe Pavilion, overlooking the beautyful panorama below. The Pavilion is at the same height and level of the Imperial Triclinium (a secunday building), but its opus sectile pavements show that it belonged to the imperial 'noble' quarters.

Piazza d'Oro (Golden Hall): a view of the porch, surrounding a vast garden.

It was a surveilled access and check-point, which through a small concealed staircase gave acces to another long artificial esplanade, located east of the Imperial Palace, reaching south the Golden Square (Piazza d'Oro) (n. 15). Piazza d'Oro is a vast building with a great rectangular open court embellished with flower-beds and water basins, surrounded by a double porch. Ont its eastern side was a series of rooms including a Triclinium, while on its southern side, opposite the entrance, was a monumental exedra with niches for statues and fountains. On the two sides of this central exedra were groups of halls covered with vaults and opened on a small cavaedium. All rooms were paved with opus sectile pavements and their walls still bear traces of the marble revetment reaching up to the ceiling. In situ are still visible some fragments of a marble frieze representing hunting scenes.
The plan of Piazza d'Oro is very similar to that of Hadrian's Stoa in Athens, which was a Library built by Hadrian in the same period of time (123-125 a.D.). This suggests that Piazza d'Oro was the great Library of the Villa, suited for a cultured emperor such as Hadrian (for a discussion on the subject see De Franceschini 1991, Piazza d'Oro p. 469-478)

The subterranean road running underneath Piazza d'Oro, wich reached up to the Great Trapezium.

From the triclinium of Piazza d'Oro one could enjoy the view over a beautyful landscape with an oval structure which has been interpreted as a Gladiator's Arena (n. 15a). A similar building was discovered in the Villa of the Quintili on the Appian way in Rome; very little is known about both, so this is just an hypothesis.
Under Piazza d'Oro ran a subterranean road, linked to the so-called Grande Trapezio (n. 34), the main subterranean road system spanning for more than 4 kilometers, with traces of the passage of heavy carts - see Section Three, Upper Quarters..