sentences:  In encouraging full access to all the sites, by marking them on navigation charts and by producing interpretive materials in exhibitions, pamphlets and on the plaques, the wrecks have become part of a 'museum-without-walls' concept.All of the wrecks are protected under Commonwealth legislation in the "Historic Shipwrecks Act 1976" and State legislation in the Maritime Archaeology Act (1973).The Rottnest Island Wreck Trail was the first in the Southern Hemisphere and the first of Western Australia's heritage trails.