Below the ground level of the piazza is this restored 2nd-century-AD amphitheatre, discovered in 1901 by construction workers. It was excavated in the 1930s to reveal a perfect horseshoe that actually extends under the rest of the square to originally seat 15,000. A little colonised by weeds, it's nonetheless an impressive centrepiece to Lecce's main communal square. Walking tours available at the nearby tourist office include the history of the amphitheatre.