It was called "The Yellowstone Act," a law passed by Congress in 1872 that created America's first national park.
With its iconic, steam-spouting geysers, including one called "Old Faithful," Yellowstone in Wyoming was the first park in the world to be set aside for protection by a national government. Now there are about 1,200 such protected places around the globe.
In this country, rangers watch over much more than our 394 spectacular national parks and battlefields.
The National Park Service umbrella spreads across hundreds of seashores, rivers, cemeteries, trails, monuments, and historic sites as well - even an ocean reef in the U.S. Virgin Islands, a tallgrass prairie in Kansas, and an active volcanic field in Hawaii in which molten lava flows into the sea each day.
You'll get tours from Park Service rangers in places that don't have a single mountain or memorial. An old Minuteman missile range in South Dakota, for instance. A big trainyard full of steam engines and vintage railroad cars in Pennsylvania.
The spot in the high Utah desert where a golden spike was driven in May of 1869, as rail lines from the east and west came together to create the Transcontinental Railroad.
And not all our great memorials are clustered on the National Mall in Washington. For example, rangers oversee somber memorials in Oklahoma, marking the site where a domestic terrorist blew up a federal building in 1995, killing 168 people; and the memorial to those aboard United Airlines Flight 93, who perished when foreign terrorists plunged it into a Pennsylvania cornfield on September 11, 2001.
If you're looking for an uplifting memorial - literally - the Park Service runs one amid the dunes of North Carolina, where the Wright Brothers first took powered flight in 1903.
These national treasures can't go anywhere, of course, but some people call them our most popular export. Our wide-open and historic places intrigue the world and bring so many foreign visitors to the United States that brochures at several national sites are printed in three, four - as many as seven - languages.