Reservoir of Sau Nature · Tavertet, Osona, Barcelona The pantà de Sau is a reservoir on the river Ter created by a dam located in the municipality of Vilanova de Sau, at the foot of the Guilleries range, which also extends into the municipalities of Les Masies de Roda, Tavertet and l'Esquirol, in the comarca of Osona. Together with the Susqueda and Pasteral reservoirs, it regulates the Ter to supply water to the metropolitan area of Barcelona, Girona and the Costa Brava, besides generating hydroelectric power. It was planned in 1931 and built between 1947 and 1963, submerging the old village of Sant Romà de Sau, whose 11th-century Romanesque bell tower, recorded as the oldest submerged church in the world still standing, emerges when the water level drops. Photo: Quico Llach (Public domain) What to see and do in Tavertet