An Act of Congress.
National is an adjective; monument is a noun.
Petroglyph National Monument was created in 1990.
In 1890.
The Washington Monument
The Giant Sequoia National Monument comprises 328,315 acres of California's Sequoia National Forest. It was designated a National Monument in April 2000.
The state that Homestead National Monument is in is Nebraska.
Yes, Pipestone National Monument. www.nps.gov/pipe
Wupatki National Monument was created in 1924.
National Monument of Scotland was created in 1829.
Soldiers' National Monument was created in 1869.
Cabrillo National Monument was created in 1913.
Mukuntuweap National Monument was created in 1909.