The Clitunno Tempietto

The so-called Temple of Clitumnus is a small early medieval church that sits along the banks of the Clitunno river in the town of Pissignano near Campello sul Clitunno, Umbria, Italy. In 2011, it became a UNESCO World Heritage Site as part of a group of seven such sites that mark the presence of Longobards in Italy: Places of Power.

Although the classical architecture and location suggests it may have been the Temple to Jupiter Clitumnus mentioned by Pliny, archaeologists found that the structure was built later, before the 6th century, as a church and had been constructed mainly of material taken from ancient Roman structures in the neighbourhood.

Source: Wikipedia