The underground chapel hidden beneath Chinon

The Chapelle Sainte-Radegonde is an underground structure in Chinon, French department of Indre-et-Loire in Centre-Val de Loire region. Originally known as a miraculous well, it was turned into a chapel around the 11th or 12th century, but the exact date is uncertain, as it was first mentioned in written sources in 1269. A mural depicting a hunting scene from the end of the 11th century has been discovered in the chapel. The chapel was named after Saint Radegonde, although it is not clear if she was the one who gave the chapel its name. However, she is said to have visited the site. The chapel was abandoned during the French Revolution but was bought by the town of Chinon in 1957 and restored. Today, it serves as a museum of traditional popular arts of Chinon.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons