This coffee shop lies hidden beneath a historic church.

A cluttered and astounding collection of antiquities and curiosities.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

A student driver's nightmare.

Eighty million natural history specimens call this gargantuan museum home.

Overlooking the burial ground is a tower designed to prevent thieves from snatching the recently deceased.

Remnants of the 16th-century defensive wall still stand unassumingly within Edinburgh.

The most loyal of little dogs, or a Victorian era publicity stunt?

A 18th century graveyard and its astonishing cortege of macabre iconography.

This extinct volcano rises above Edinburgh and is special for its panoramic views over the city.

This monumental work of art symbolizes the coming together of a previously divided city.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Metro station with a claim to rock n' roll fame.

Berlin's old airport.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

An abandoned NSA listening post on Berlin's "Devil's Mountain."

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

A remnant of the last Ice Age, this lake is surrounded by fascinating rock formations.

Minnesota's oldest and deepest mine is now an underground physics laboratory.

This picturesque cliffside beacon no longer calls to sailors but shines once a year in honor of a famous shipwreck.

A four story, football field-sized, nine-grotto creation made of shells, minerals, and rare stones.

This posh mansion began as a family's estate and ended as the site of a murder ripped from the pages of a pulp novel.