The Nature Conservancy (TNC) is a charitable environmental organization, headquartered in Arlington, Virginia, United States. Founded in 1951, The Nature Conservancy has over one million members and has protected more than 119,000,000 acres (48,000,000 ha) of land and thousands of miles of rivers worldwide. The largest environmental nonprofit by assets and revenue in the Americas, The Nature Conservancy ranks as one of the most trusted national organizations in Harris Interactive polls every year since 2005. - from Wikipedia