In the days before house numbers, these colorful signs held clues about various buildings' purposes.

This unattributed sculpture in Amsterdam is hiding in plain sight.

This plaque marks the former home of one of the first women physicians in the Netherlands.

A set of seven houses, each built in a style that represents a European country.

This abandoned island off the Venetian coast has been a radical monastery, a political prison, and a secret Nazi base.

The pile of books behind the dignified writer gave the statue a most undignified nickname.

Its incredible collection preserves 170 years of sewing machine history.

Standing at 21-feet tall, this space cowboy adds to the legacy of Route 66's muffler men.

This abandoned, windowless concrete block is one of the strangest buildings in Tulsa.

An immersive art experience built by local arts collaborative, Factory Obscura, in the building formerly known as The Womb, a psychedelic arts center founded by the frontman of the Flaming Lips.

One of the best examples of Art Deco architecture in the United States.

The only retired U.S. nuclear missile silo that is open to the public.

The 10,000 Torii shrine.

This religious museum resides in a church crypt next to the founder's house.

England's most famous front door has an accidental doppelganger.

Behind one of the world's most impenetrable vaults is a massive collection of retail silver.

Since 1887, this old-school shop has stacked its shelves with extraordinary coffees and teas.

The majority of the museum's large collection is held in a storage space open to the public a few times a year.

This local gem houses the largest collection of pre-Raphaelite paintings outside of the U.K.

A wrecked ship dating back to the American Revolution was only recently discovered off the Delaware coast.

Its unique collection details the history of the state's svelte railroads.

This World's Fair showpiece was built in Chicago, but shipped to Maine.

This candy-striped tower is the farthest east you can go in the United States.

The eccentric mansion of one the most popular horror authors of modern times.