Visit on a Sunday morning to see some killer tricks.

A chaotic collection of coin-operated slot machines designed to delight and disturb in equal measure.

In an arboretum with hundreds of memorials to the fallen, this one might be the most poignant.

Vast fan-shaped British cemetery honouring American servicemen lost in World War II.

There are hundreds of secret WWII bases hidden in British forests. Built to fight a Nazi invasion, they remained unknown for decades.

These morbid carvings remind churchgoers of the inevitability of death.

A hundred copies of Antony Gormley's naked body stare out across the water.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

The biggest and deepest Cold War bunker open to the public can be found in southeast England.

This silent sentry in the crypt below a large Gothic cathedral is often knee-deep in water.

A museum wholly devoted to juvenescence.

Art Deco and “Wrenaissance” mash-up, this recently restored royal residence has been home to kings and comes with secret monkey passages included.

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

A network of concealed passageways lies within a busy London Underground station.

This beautiful Victorian ironwork masterpiece was built to keep London from smelling like poop.

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

A hands-off space for graffiti artists to hone and display their skills.

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

In an isolated field near a dilapidated barn stands this chilling portrayal of the plight of the Nuba peoples of Sudan.