Warsaw's fantastically preserved gasworks...almost.

A massive mammoth bone has been on display inside this church since the 18th century.

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

This massive concrete sculpture is said to be the heaviest communist monument on Earth.

A controversial artwork draws attention to the dark history of Prague's "Suicide Bridge."

A surreal statue honoring Prague's favorite literary son.

This spooky statue sits outside a famous Prague theater.

A saintly relic hidden in a Prague church basement.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

This nearly 200-year-old restaurant's history includes an exiled French prince, JFK, and a very hungry Daniel Webster.

The tomb of Increase Mather and his son Cotton, influential colonial ministers obsessed with the occult.

A collection of intricate sculptures so small they have to be seen through a microscope.

A two-way chairlift system between Zugliget and the highest point in the city.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

The remnants of a Gilded Age elegance preserved in the middle of a stark modern tower.

The former locus of Boston's high culture has been shuttered and buried for over 70 years.

Ralph Waldo Emerson spent two years living here decades before it became a Frederick Law Olmsted-designed park.

Built in 1821 using rooms from another estate, the Phillips House is the only historic home on scenic Chestnut Street open to the public.

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

A museum befitting the city responsible for supplying the majority of the world's LSD.

The remains of a ruined mansion memorialize the 1906 earthquake.

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.