Church of San Gaetano alle Grotte, Early Christian church and archaeological site in Piazza Carlo Alberto, Catania, Italy.

Church of San Gaetano alle Grotte is an Early Christian structure with two distinct levels built over each other. The upper sanctuary sits above an underground chapel carved into and constructed within a natural lava cave system, accessed by a steep narrow staircase of lava stone.

The original building, known as Santa Maria La Grotta, was built between 260 and 300 AD. It was reconstructed multiple times following the Muslim conquest of Sicily and the devastating 1693 earthquake that reshaped the region.

The lower church is twinned with the Russian Orthodox monastery of Divnogorje and hosts the Catania Orthodox community for Sunday Masses. On 5 June 2009 it was the setting for the investiture of new members of the Unione Cavalleria Cristiana Internazionale, celebrated by rector father Antonino Lo Curto.

The lower church is reached by a steep lava-stone staircase built in the Norman period, replacing the earlier sloping descent. The crypt sits below the level of Piazza Carlo Alberto, next to the Santuario della Madonna del Carmine. The Carmelite friars restored both church and crypt in 1958.

The underground space was originally fed by a natural water source and an ancient well, which caused regular flooding. Over time, sediment filled the structure and halted these water movements.