The National Parks: America's Best Idea
A website of the Convention on Biological Diversity with good links to other organizations and projects.
Protected Areas and World Heritage
A UNEP World Conservation Monitoring Centre site with access to the World Database of Protected Areas.
World Commission on Protected Areas
A project of the World Conservation Union (IUCN). The website has full text of documents and other publications.
World Database on Protected Areas
A joint project of IUCN and UNEP, WDPA provides data on marine and terrestrial protected areas.