The garden plan is laid out on a central axis with subsidiary cross-axes of carefully varied character, refreshed by some five hundred water jets in fountains, pools and water troughs, supplied by the Aniene, which is partly diverted through the town, and by the Rivellese spring, which supplies a cistern under the villa's courtyard.
The Villa's uppermost terrace ends in a balustraded balcony with a sweeping view over the plain below. Double stairs flanking the axis lead to the next garden terrace, with the Grotto of Diana, richly decorated with frescoes and pebble mosaic to one side and the central Fontana del Bicchierone ("Fountain of the Great Cup") attributed to Bernini, where water issues from a seemingly natural rock into a scrolling shell-like cup. The Fontana dell'Ovato ("Oval Fountain") cascades from its egg-shaped basin into a pool set against a rustic nymphaeum.
To descend to the next level, you take stairs at either end - the elaborate fountain complex called the Rometta ("the little Rome") is at the far left - to view the full length of the Hundred Fountains on the next level, where the water jets fill the long rustic trough, and Pirro Ligorio's Fontana dell'Ovato ends the cross-vista. It is possible to walk behind the water through the rusticated arcade of the concave nymphaeum, which is populated by marble nymphs by Giovanni Battista Della Porta. Above the nymphaeum, the sculpture of Pegasus alludes to the fountain of Hippocrene on Parnassus, haunt of the Muses.
This terrace is united to the next by the central Fountain of the Dragons, dominating the central perspective of the gardens, erected for a visit in 1572 of Pope Gregory XIII whose coat-of-arms features a dragon. Central stairs lead down a wooded slope to three rectangular fishponds set on the cross-axis at the lowest point of the gardens, terminated at the right by the water organ and Fountain of Neptune.