Location: M65M+H2 Conquereuil, France
Lost Civilizations / Ruins
by @anton
According to local tradition, the city of Coëtma (recently corrupted to Coisma), near Conquereuil, was swallowed into a vast depression in the ground, believed to mark the site of the vanished settlement.
Like many sunken cities in Breton folklore, Coëtma is said to reveal its presence on major religious feast days, when the bells of its church can still be heard ringing beneath the earth. Local accounts also mention large wooden posts discovered deep in the ground, interpreted as the remains of the lost city.
Source : Pitre de Lisle https://gallica.bnf.fr/ark:/12148/bpt6k6157467j/f19.image.r=coetma
Part of the legend: The Sunken City