A geological mystery on Camelback Mountain.

The former headquarters for Whitey Bulger and the notorious Winter Hill Gang.

The sweetest graveyard in the world is filled with headstones for dearly de-pinted ice cream flavors.

A three-piece musical sculpture installed between the subway tracks at Kendall Station near MIT.

This rare polygonal meeting house is rumored to be built in a circle so that the devil has nowhere to hide.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

This small museum nestled inside a souvenir shop is dedicated to Sweden's most well-known toy.

A 130-year-old urinal is the oldest of Stockholm and perhaps all of Sweden.

Stockholm's tiniest statue is of a small boy looking at the Moon.

A concrete mushroom that divided Stockholm residents for nearly a century.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

This homeless brass fox tugs at your heartstrings from the foot of a Stockholm bridge.

Stockholm's deepest subway station is also a stunning ecological wonder.

At low tide, you can see the remains of a 17th-century ship just off a Stockholm island.

The Swedish flag over this small naval fort signals that the nation is at peace.

It houses the remains of a 17th-century version of the Titanic.

A spectacular Petrine Baroque summer palace commissioned for Catherine I by Peter the Great.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

A former imperial sea-fortress and Soviet prison.

Disused seaplane hangar gets a second life as the jaw-dropping home of Estonia's museum of maritime history.

Estonia's largest creative city is a vibrant bohemian hub located within a former industrial complex.

A subterranean house of worship carved right out of the bedrock.

These enormous, stern-faced statues greet visitors with lanterns, and sometimes costumes.

This endearingly discomfited urinating statue commemorates the sneaky pees had by us all.