Officials formally dedicated the Stonewall National Monument on Monday — the first national monument to be established in honor of the LGBT movement.

Announced by President Barack Obama on Friday, today’s event was the official ceremony, held outside of the Stonewall Inn in New York City. The dedication was lead by Valerie Jarrett, one of Obama’s Senior Advisors, and was attended by political proponents such as NYC Mayor Bill de Blasio, Sen. Kirsten Gillibrand (D-NY) and Secretary of the Interior Sally Jewell.

In addition to being the first LGBT monument, Stonewall is also the second national monument to commemorate a site of civil unrest — the first being the Pullman National Monument, which Obama designated in February of last year.

The Stonewall National Monument covers approximately 7.7 acres in Manhattan’s Greenwich Village, encompassing the Stonewall Inn, Christopher Park and the surrounding area that was the site of the Stonewall riots.

Often referred to as the birthplace of the modern gay rights movement, the Stonewall Riots began in the early hours of June 28, 1969, while New York City police were conducting a raid on the original Stonewall Inn. At a time in history when it was illegal to live openly as a homosexual, such raids were not uncommon at gay bars and dance halls such as Stonewall. What distinguishes the events of this particular night at Stonewall is that, rather than dispersing as usual, a crowd of protesters gathered outside during the raid. Continuing to grow larger in size, the crowd also became more vocal and more angry — eventually turning into a full-on riot.

As the National Park Service notes:

… the crowd became increasingly angry and began chanting and throwing objects as the police arrested the bar’s employees and patrons. Reinforcements were called in by the police, and for several hours they tried to clear the streets while the crowd fought back. The initial raid and the riot that ensued led to six days of demonstrations and conflicts with law enforcement outside the bar, in nearby Christopher Park, and along neighboring streets. At its peak, the crowds included several thousand people.

Stonewall marks the 23 national monument designated by President Obama under the American Antiquities Act of 1906. The 44th President of the United States has used this authority more than any other president in history, placing more than 3.9 million acres of land under federal protection. He is also the only president to use the act to preserve sites of modern political activism, as seen in his designations of the César E. Chávez, Pullman and Belmont-Paul Women’s Equality national monuments.

Established during the presidency of Theodore Roosevelt, the Antiquities Act is meant to protect “any object of antiquity,” which has traditionally been taken to mean sites of archaeological significance. Stonewall joins the likes of the Grand Canyon, the Aztec Ruins in New Mexico and Thomas Edison’s Laboratory.

Specifically, the act says, “… the President of the United States is hereby authorized, in his discretion, to declare by public proclamation historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest that are situated upon the lands owned or controlled by the Government of the United States to be national monuments.”

The Antiquities Act further stipulates that the President “may reserve as a part thereof parcels of land, the limits of which in all cases shall be confined to the smallest area compatible with proper care and management of the objects to be protected.”