The 11 columns which remain of this temple are built into a 19th century palazzo which now houses the Rome Stock Exchange.
At 12.8m high, the columns are constructed entirely of marble from Marmara Island in Turkey(also used for Hagia Sophia in Istanbul.)
Behind the railings, deep excavation exposes the original ground level 5 metres below the present square. Although both ends and the other side of the temple disappeared long ago, traces of the vaulting underneath the front steps have been found under Via dei Burrò showing that it would have faced towards the east and probably had eight columns across the front and thirteen down the sides.
There is no inscription to identify the temple as to that of Hadrian (who died in AD 138), but one was dedicated to him by his successor Antonius Pius in AD 145, and this could be that very one.
The tiny cocktail bar opposite the temple is called Salotto 42 and serves fantastic cocktails.