The 17C and 18C façade of St Peter's Palace (Palais St Pierre) looks onto this square, where a monumental lead fountain by Bartholdi stands: the four horses symbolise the rivers flowing into the ocean. The square is the hub of the town's activity and was the setting of the execution of Cinq-Mars in 1642. The square was given a facelift by Daniel Buren, who paved it with granite and added 14 pillars and 69 water jets. The night lighting completes the development.