National monuments over time

President Theodore Roosevelt established Devil’s Tower in Wyoming as the nation’s first national monument in 1906.   (Stephen Berend / Associated Press)

In 2014 President Obama added 1,665 acres of federal land to the California Coastal National Monument in Mendocino County.  (Brant Ward / Associated Press)

President Obama designated Ft. Ord, a decommissioned military base in Northern California, as a national monument in 2012.   (Vern Fisher / Associated Press)

The Papahanaumokuakea Marine National Monument in Hawaii was established by President George W. Bush in 2006.   (Louiz Rocha / Associated Press)

President Obama set aside 346,000 acres of Southern California’s San Gabriel Mountains -- including the East Fork of the San Gabriel River, a popular recreation spot for families -- as a national monument in 2014.   (Francine Orr / Los Angeles Times)

Paul Chavez visits the grave of his father, Cesar Chavez, at the Cesar E. Chavez National Monument in Keene, Calif. President Obama established the monument in 2012.   (Irfan Khan / Los Angeles Times)

The Statue of Liberty is part of a national monument established by President Calvin Coolidge in 1924. The monument was later enlarged under Franklin D. Roosevelt and Lyndon Johnson.  (Spencer Platt / Getty Images)