President Wilson on Aug. 25, 1916, created a National Park Service that would "... conserve the scenery and the natural and historic objects and wild life therein, and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for future generations."
Ninety-seven years later, the system has grown to oversee more than 84 million acres of public lands. To mark Founders Day on Sunday, parks across the nation will waive entrance fees.
The deal: In addition to free entrance, many parks have special free events planned too.
--At Theodore Roosevelt National Park, the "president" will show up between 11 a.m. and 1:30 p.m. local time at the South Unit Visitor Center in Medora, N.D.
--Arches National Park near Moab, Utah, will host events on culture and natural diversity all day at the park's visitor center.
--Yosemite National Park, which received its status in 1890, invites visitors to help with removing invasive species, thinning small trees and other restoration work. (Check conditions from the nearby Rim fire outside the park that has temporarily closed one entrance.)
When: The fee-free day applies to Sunday only.
Details: Only national parks and historic sites are free for Founders Day; national forests such as the Angeles, San Bernardino, Los Padres and others will require the usual $5 Adventure Pass entry fee.
Information: National Park Service Founders Day 2013