National Football League | National Register of Historic Places | National Hockey League | Act of Parliament | Act | England national football team | National Basketball Association | National Science Foundation | National Geographic | National Trust | National Endowment for the Arts | National Geographic Society | Argentina national football team | National Trust for Places of Historic Interest or Natural Beauty | National Park Service | National League | Australian National University | National Guard | National Geographic Channel | National Institutes of Health | National Guard of the United States | National Collegiate Athletic Association | United States National Research Council | Statute Law Revision Act 1948 | National Portrait Gallery | National Academy of Sciences | Indian National Congress | United States men's national soccer team | National Research Council | Royal National Theatre |
Project Learning Tree (PLT) was created in 1976, after passage of the first National Environmental Education Act in 1970 and celebration of the first Earth Day in 1970, raised the profile of environmental education in the United States.