It is the most drawn temple in Italy: a round stone building on the edge of a gorge, with the waterfall below and empty air around. It was built in the first century before Christ, and in the eighteenth and nineteenth centuries every traveller on the Grand Tour painted it, engraved it and set it in watercolour, often adding shepherds and ruins that were not there.
What to see
Of the temple there remain ten Corinthian columns out of eighteen, the circular cella with its door and windows, and the carved frieze with ox skulls and garlands. It is small, and that is the point: its fame depends not on size but on where it was put, poised over the ravine of the Aniene.
Beside it is a second temple, rectangular, which the people of Tivoli call the Sibyl's; to whom the two buildings were really dedicated is not certain, and the names we use come from tradition rather than documents. Below, the gorge with the great waterfall is part of the park of Villa Gregoriana.
Visiting
The temples are at the top of the cliff, at the upper entrance to Villa Gregoriana; they can be seen free from outside, from the little square, while going down into the gorge to see the waterfall needs the park ticket, which has seasonal closing. Half an hour for the temples, two hours with the gorge.
Our editors' tip
Stand on the opposite side of the valley, on the path going down into the gorge, and look at the temple from below: it is the same framing as two hundred prints kept in museums across Europe. From there you realise those travellers were not exaggerating the landscape, they were simply choosing the spot well.