The National Park Service turned 100 years old Thursday, a milestone being celebrated everywhere from Independence Hall to Mount Rainier.

President Woodrow Wilson signed the act creating the National Park Service on Aug. 25, 1916. At the time, it charged the new federal bureau with managing 35 national parks and monuments, including such stalwarts as Yellowstone, Yosemite and the Grand Canyon. Today, the National Park System comprises 413 sites covering some 80 million acres across the country.

The park system preserves natural wonders like the Redwoods while also maintaining historical sites like the National Mall.

Philadelphia has four sites managed by the National Park Service, including Independence National Historical Park. Established in 1956, the park features Independence Hall, the Liberty Bell, Washington Square and Christ Church. Millions of people have visited the sites, among them are dignitaries like Abraham Lincoln and Pope Francis.

To celebrate the milestone anniversary, here's a look back at Independence Hall through the years. Photos are courtesy of PhillyHistory.org, an online photo archive containing millions of photos form Philadelphia dating to the 1800s.

Source/PhillyHistory.org An American flag made out of balloons hangs in front of Independence Hall during the Bicentennial celebration in 1976.

Source/PhillyHistory.org The Liberty Bell sits in a new chamber across the street from an illuminated Independence Hall on Feb. 4, 1976. The historic bell was moved from inside Independence Hall prior to the Bicentennial celebration.

Source/PhillyHistory.org President Richard Nixon signs a revenue sharing bill outside of Independence Hall on Oct. 20, 1972.

Source/PhillyHistory.org A militia fires muskets outside of Independence Hall as part of a Freedom Week celebration on July 1, 1967.

Source/PhillyHistory.org An aerial view, taken sometime in 1966, captures Independence National Historic Park 10 years after it was established on July 4, 1956.

Source/PhillyHistory.org President John F. Kennedy and Mayor James Tate admire the Liberty Bell while visiting Independence Hall on July 4, 1962.

Source/PhillyHistory.org Spectators watch a fire demonstration conducted outside Independence Hall in 1937.

Source/PhillyHistory.org President Woodrow Wilson speaks outside Independence Hall on July 4, 1919 – eight months after World War I ended.

Source/PhillyHistory.org The Liberty Bell is displayed on the back of a truck parked outside Independence Hall on Oct. 25, 1917. Earlier that year, the United States declared war and entered World War I.

Source/PhillyHistory.org The East Room on the second floor of Independence Hall undergoes renovations in 1896.