The oldest arched-covered bridge in Virginia has truly withstood the test of time.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

A former major munitions plant that has been converted into a sprawling art space.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

The ruins of an 18th-century mansion that was once named "Mistake" by the man who had it built.

These unusual rooms on wheels are holdovers from the 1960s.

This train station inspired the name of a 1970's rock band and provided the backdrop for their album cover.

The United States's largest hand-dug well is topped with a state-of-the-art museum.

This erect, phallic geological spire wasn't always named so domestically.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

This replica stave church looks like a piece of Norway was simply plopped down in South Dakota.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

The first declared National Monument in the United States.

At the time of its completion, it was the tallest dam in the world.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

This rustic old building is said to be the most photographed barn in America.

One of the largest collections of wildlife art in the United States, built into the side of a cliff in rural Wyoming.

This stretch of beach along California's central coast is a busy highway for the largest seal in the northern hemisphere.

The second-largest giant sequoia in the world.

Quite simply the largest tree in the world (by volume).