In 2016, the National Park Service will celebrate 100 years as steward of the Nation's most cherished natural and cultural resources. As the keeper of 401 park units, 23 national scenic and national historic trails, and 58 wild and scenic rivers, NPS is charged with preserving these lands and historic features that were designated by the Nation for their cultural and historic significance, scenic and environmental worth, and educational and recreational opportunities. Additionally, the NPS further helps the Nation protect resources for public enjoyment that are not part of the national park system through its grant and technical assistance programs.