It is said that coins washed in the waters here will miraculously multiply.

Narrow passes cut out of mountains surround the medieval capital of Japan.

The "largest bathroom stall in the world" offers a unique pit-stop experience.

The last remaining predreadnought battleship in the world has been a museum for nearly a century.

This mysterious medieval grotto holds a grid of sacred wells of unknown purpose.

Emerging from the sidewalk, this sculpture of a whale commemorates the importance of baleen in traditional Japanese puppetry.

A clone of a cloned tree that was so important it allegedly had its own guards.

Every drop of D.C. tap water flows through this old waterworks.

There's a crumbling old mansion inside the Smithsonian National Zoo.

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

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

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

Senators used to relax in the nearly forgotten marble tubs now hidden in the U.S. Capitol Building's basement.

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

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

They sort through millions of dollars worth of diplomatic gifts on behalf of the government.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.