The Oparara Basin is a remote section of Kahurangi National Park near Karamea on the West Coast of the South Island of New Zealand. This hard to reach spot features a stunning array of caves, arches (including the Oparara Arch, which is the largest natural rock arch in the southern hemisphere,) dense rain forest and a dazzling amount of wildlife including the protected cave spider, Spelungula cavernicola and the endangered Blue Duck. This place is absolutely amazing and highly recommended if you travel to the West Coast.