A 3 m-tall trilithon dolmen from 1928. It's pretty impressive - it has two vertical and one horizontal stones, and a large menhir stands nearby.
Wikipedia (French) http://fr.wikipedia.org/wiki/Dolmen_des_Trois_Pierres_%28Saint-Nazaire%29
Address 2 Rue Gauloise, Saint-Nazaire 44600, France
Coordinates 47°16'46.383" N -2°12'21.725" E
