Admission free to any national park.

Volunteers, who help clear debris on National Public Lands Day on Sept. 18, will be rewarded with a free entry day any time during the next year at any public land site. The 11th annual volunteer-supported event attracts thousands of people nationwide to clear trails, build bridges, plant trees and participate in other activities to benefit the nation's public lands.

This is the first time the free day is being implemented. "The fee-free day has been something we've been working toward for several years," said Patti Pride, director of National Public Lands Day. "Our goal was to reward our volunteers with a free day at the public land site of their choice."