The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

Looming communist pillar with a Czech twist.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Walk through Czech history in Prague's largest graveyard.

The hidden lair of an alchemist rediscovered in a 2002 flood.

Macabre astrological automaton clock dating to the late 1400s.

Once designed as the entrance to Buckingham Palace, this structure was later relocated and stands as a victory arch.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

Scattered throughout London are ancient remnants of the city's former bounding wall.

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

Hear the quietest sound from across the dome.

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

One part local history, 99 parts gruesome haunted house.

A two thousand year old brothel uncovered in Northern Greece.

An abandoned Byzantine fortress and notorious prison.

Once a meeting point for great thinkers, and the midpoint of the country.

Site of the first radio and telephone broadcasting companies in Copenhagen.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

This ordinary street was made infamous by a legendary visit from the devil.

This bridge's unique architecture honors nautical heritage and encourages self-awareness.