Chapelle Sainte-Radegonde

The Chapelle Sainte-Radegonde or Sainte-Radegonde Chapel is an underground structure, a former oratory converted into a chapel, on the slope of the Sainte-Radegonde hill, east of the historic town center of Chinon, in the French department of Indre-et-Loire in the Centre-Val de Loire region. The site has probably been known since antiquity as a well whose waters were reputed to be miraculous; tradition has it that the hermit Jean le Reclus was buried there; the main developments leading to the creation of a proper chapel, however, date back to the 11th or 12th century.

Source: Wikipedia — Chapelle Sainte-Radegonde (CC BY-SA 4.0)