France's Subterranean Church - Église monolithe Saint-Jean

Constructed around the 8th century, the Église monolithe Saint-Jean is far from ordinary. Instead of a sundry facade, one encounters a subterranean curiosity, hewn into the cliff. Secured within the Church's lower level is the Piscine baptismale, an 8th-century relic expanded by the 12th-century Benedictine monks. Influenced by visits to Cappadocia, they adapted the techniques of excavation for this project. As the voices, taillées en plein cintre, soar nearly 20m, the church boasts a robust collection of octagonal pillars.

A gallery ascends three sides, accessible by a rock-carved staircase. Measuring 27m long and 16m wide, it is one of Europe's largest monolithic churches, with an abside hémicylindrique voûtée en cul de four. The church boasts a towering Roman stone reliquary (6m tall) and venerable crypt older than the Christian era, with medieval stalls still visible. Sunlight illuminates the sanctuary through three expansive windows on the eastern wall. Dedicated to St.

John during the Wars of Religion in the 1550s, it was later repurposed as a saltpeter factory during the French Revolution. A record 65,000 visitors flocked to the church in 2014. Renovation work is slated to begin in 2015.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons