National Public Lands Day (NPLD) is celebrated annually at public lands in the United States on the fourth Saturday of September. A signature event of the National Environmental Education Foundation, it promotes both popular enjoyment and volunteer conservation of public lands. Three federal agencies and 700 volunteers launched the first National Public Lands Day in 1994. By 2010, participation grew to 170,000 volunteers at over 2,000 sites across the country, the District of Columbia and U.S. territories. In addition to National Public Lands Day being a fee-free day (free entry day) at many federally managed lands, volunteers who participate at federal land sites are rewarded with coupons for free entry into their favorite federal public land areas that have entrance fees. The 2008 event featured an initiative to plant one million trees in honor of the 75th anniversary of the Civilian Conservation Corps.