Boaters enjoying a warm summer afternoon on the Estanque Grande (Great Pond) in Retiro Park, Madrid, Spain. Dating from 1636, the pond covers an area of 9 acres (37,000 sq meters). It was originally a reliable source of water for the royal palace and gardens that stood nearby. When the City of Madrid took ownership of the park in 1868, the pond took on a recreational purpose. During the summer months, anyone can rent a boat for 6 euros/hour Monday through Friday and 8 euros/hour weekends and public holidays.