The National Park Service, an agency within the Department of the Interior, manages the Delaware Water Gap National Recreation Area (Park). Noyes was driving her car southerly on Route 615 on the New Jersey side of the Park with Kathleen and Kaylyn Merando as passengers. Noyes drove the car by a twenty-seven-foot tall red oak tree that was about six yards off the road. The tree's natural growth caused it to lean with its branches extending over the roadway. More than ten years before, an unknown person wielding a chainsaw had 'topped' and delimbed the tree, leaving it standing in a 'Y' shape with no bark or branches and with the dead tree pole leaning toward the roadway. As their car passed nearby, the tree fell and crushed the car instantly killing Mrs. Merando and Kaylyn. P sued the United States (D). P alleged that the District Court had subject matter jurisdiction pursuant to the Federal Tort Claims Act (FTCA). D moved to dismiss the complaint for lack of subject matter jurisdiction on the basis of the discretionary function exception to the FTCA. The trial court agreed and dismissed the case. P appealed.