The Snares Islands (or just 'Snares') are one of five subantarctic island groups that became UNESCO World Heritage in 1998, because of their unique flora and fauna. All New Zealand subantarctic Islands enjoy the highest level of protection available under New Zealand legislation. The Snares are considered as so called "minimum impact islands" meaning that landings are not permitted (not for tourists, not for scientists) unless the Department of Conservation did not issue a special permit. The Snares consist of one Main Island (North East Island) that is surrounded by several smaller islands and rocks (e.g. Broughton Island, Alert Stack, the Daption Islands in the north), and a group of islands that are known as the Western Chain. The Snares are the only subantarctic island group that is free from any introduced terrestrial mammals apart from humans, of course. And, in the past, even humans seldom showed up, which was different on the other Islands that were either used as whaling- or sealing bases or as farming grounds. The Snares were never inhabited by humans. Because of the above mentioned complete absence of terrestrial mammals, the Snares form an intact habitat for birds and seals. Sea birds use virtually every square meter on the islands for nesting and resting.