The National Park Service is turning 103 years old and to celebrate Founder’s Day all Grand Canyon visitors can enter the park for free on Sunday, August 25th.

Fees will remain for tours, camping, reservations and concessions. Charges will resume for those staying at the park beyond Sunday.

Those planning to visit the part on Founder’s Day should expect large crowds and long lines at entrance stations. If you are driving into the park it is advised to arrive before 9 a.m.

To avoid the backup, the park suggests using the shuttle bus to the Grand Canyon Visitor Center from the community of Tusayan. Shuttles will run daily every 20 minutes from 8 a.m. to 9:30 p.m. at four pickup points in Tusayan, which is 20 minutes from the park.

If traveling to the Grand Canyon isn’t in your plans this weekend, the park’s  admission fee will be waived again on Sept. 28 to honor National Public Lands Day.

The Grand Canyon celebrated its official 100th anniversary as a national park in February and is commemorating the milestone with events throughout the year.