A historic arboretum and non-conformist, non-denominational park cemetery.

The largest of London's subterranean rivers and once a mad, bad center of London life.

Collection dedicated to brands, packaging and advertising.

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.

The television series' iconic giant foot was borrowed from this classical painting.

London's smallest police station is barely the size of a phone booth.

The fountain marks the area where hundreds of accused witches were burned at the stake.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

The real clothing store that inspired a fictional spy organization's front.

This 19th-century Turkish bath house survived the Blitz of London and is now an events venue.

A memorial for public executions that dates back to the 14th century.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

This platform is now a memorial dedicated to those who were deported during the Holocaust.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This morbid scene depicts the Darwinian drama of death on the African savannah.

Creating this diorama spurred naturalist Carl Akeley to begin advocating to protect the apes.

This anonymous businessman sculpted in bronze became an enduring memorial after 9/11, and had been mistaken by rescue workers for a survivor in the rubble.