Yarmouth Castle is a square fortification, nearly 100 feet (30 m) across, with an arrow-head bastion protecting the landward side.[41] The north and west walls face the sea, protected by angular buttresses, and a 10-metre (33 ft) wide moat originally protected the south and east side, although this has since been filled in.[42] The castle's 16th-century bulwark, which originally covered the area to the west of Pier Street and the north of Quay Street, and its quay battery have also been destroyed.[43]