Since the first Europeans visited the west coast of Australia in the 17th century, Rottnest Island has seen numerous shipwrecks. The 11-kilometre (6.8 mi) long and 4.5-kilometre (2.8 mi) wide island is surrounded by hidden and partly exposed reefs whilst being buffeted by north-westerly winter gales as well as very strong south-west summer sea "breezes". It is situated 12 kilometres (7.5 mi) west of the port of Fremantle meaning that much of the maritime traffic to Western Australia's major port passes close by.