The National Park Service is celebrating its 103rd birthday with free admission at all national parks on Aug. 25.

The deal is available at more than 400 parks across the country but does not apply to activities such as camping, special tours, boat launches or transportation. Those who can't make it on Sunday can visit for free on Sept. 28, which is National Public Lands Day, and Veterans Day on Nov. 11. For more information, visit nps.gov.