San Michele, Cave church in the Fondovico district, Gravina in Puglia, Italy

San Michele is a cave church in Gravina in Puglia carved into limestone and featuring ancient frescoes, carved altars, and a network of passages. The spaces extend deep into the rock formation, with natural stone walls forming the sanctuary and surrounding areas.

The church was probably hewn between the 8th and 10th centuries from a single large block of tufa, with smaller grottoes annexed to the main hall. One grotto carries an epigraph recalling the Saracen massacre of Gravina's inhabitants in 999. The bones kept there were moved at the end of the 20th century to the municipal cemetery ossuary and to the church of San Bartolomeo.

Every 8 May the neighbourhood celebrates the Festa di San Michele delle Grotte, recalling the legendary apparition of Saint Michael in a cave at Monte Sant'Angelo. Residents decorate the streets with so-called "balloni" for the occasion. The church also hosts a Passion play at Easter.

The church is in the Fondovico (or Fondovito) district of Gravina in Puglia. The main hall is structured around 14 natural pillars dividing it into five naves with three altars. The 8 May festival fills the neighbourhood streets with decorations called balloni.

In a side grotto lie a pile of skulls and bones, long linked by legend to the 999 Saracen raid, though they were probably moved here in the 17th-18th centuries. The martyrs' relics stayed in the church until the late 20th century, then went to the cemetery ossuary and San Bartolomeo.