 In 1816 a pump room and baths were erected near the present day Clarence Pier, and by 1820 a large complex was developed including vapour baths, showers, and card playing and assembly rooms.The remaining marshland was drained, leading to the creation of "Southsea Common", some 480 acres (about 2 km2) of open grassland.Due to military requirements for clear lines of fire adjacent to Southsea Castle, the area was developed and remains today as a park and garden.