A natural history wunderkammer in the middle of the desert.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

The highest point in Arizona is an oddly snow-topped peak within the otherwise arid state.

A wild west cemetery in Tombstone, Arizona, provides a window into the Old West.

An old saloon in the West filled with history, and according to some, a few dozen ghosts.

America's only nuclear missile silo open to the public.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

See massive fossils that are over 200 million years old in northeastern Arizona.

A self-built castle made by a mysterious man.

This unassuming passageway played a key role in one of the most important events in U.S. history.

Also known as the Founding Church of Scientology.

The fountains of the U.S. Navy Memorial are annually salted with water from the Seven Seas as part of a nautical ritual.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

Before Nixon, "watergate" meant canals.

There’s a special club house at the top for the bell ringers.

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

The most accurate timepiece in the world.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

Obscure Freemasons still live in D.C.’s largest private residence.

The house where John Wilkes Booth conspired with his co-conspirators.

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

Largest Roman Catholic church in North America.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.