This oak, listed as a “remarkable tree,” is three to four centuries old. It owes its name to the abbot of the same name who took refuge there in 1791 for several years.
Created by monks in the 12th century, Lac au Duc is the largest of Brittany's inland lakes. Its 250 hectares extend between Ploërmel, Taupont and Loyat.
It is located in the middle of the Paimpont forest near the village of Folle Pensée. According to Arthurian legend, it is here that Merlin would have met the fairy Viviane.