Temple of Mars, Corseul

The remains of the largest known Gallo-Roman temple in France, a Romano-Celtic fanum located at Haut-Becherel in Corseul, Brittany, constructed in the late 1st century AD. The sacred precinct encompassed approximately 5,000 square meters and featured a central shrine with twin altars, porticoes on three sides, and semicircular pavilions with stone benches for pilgrims. The original tower reached 22 meters; today a 10.6-meter section survives as the tallest Roman masonry wall in Brittany. Archaeological evidence suggests the temple was damaged by fire during late 3rd-century barbarian invasions and abandoned by the 5th century as Christianity rose.