The second largest waterfall by volume in the U.S., Willamette Falls is outdone only by Niagara in the amount of water that is pushed northward.

Home to the only outdoor municipal elevator in the United States.

NASA's leading space science lab started by a co-founder with deep ties to the occult.

Bug-devouring flora are the stars of a special wing of the glass conservatory.

Arcadia is home to a haven for nature geeks and 80s TV lovers alike.

A relic from a forgotten bakery chain still spins atop a diner.

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

Once forgotten and built over, this historic Black cemetery now houses a poignant memorial.

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

Built to defend Washington D.C. during the Civil War, this fort became a post-war nucleus for a thriving Black community.

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

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

Before founding the American Red Cross, Clara Barton had a tremendous humanitarian impact by locating thousands of missing soldiers.

A superbly preserved example of Georgian residential architecture that was once home to one of the founders of Alexandria, Virginia.

A small but charming botanical garden that contains many exotic plant species.

This historic streetcar system has been running since the 19th-century.

A hidden three-foot-wide house separates these two regal churches.

Elaborate tile work in this railway station tells the story of Portugal.

Ancient catacombs form the foundation for this Rococo orgy of a church.

The stunning interior of this Gothic church is covered in ornate gold details.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.