This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This mundane post marks the old location of the city's main postal hub.

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

This early version of the guillotine was used to execute the man responsible for its construction.

Anonymously sculpted and donated, these sculptures made from poetry books and pages are sprinkled around the city.

Nestled among the living residents is the final resting place of an apothecary plague victim.

The last remaining bottle-shaped kilns in Scotland stand alone in an Edinburgh suburb.

This tiny weathered plot is one of the oldest Jewish cemeteries in Scotland.

This ordinary-looking mailbox has a rather explosive history.

An extraordinary library and archive dedicated to the history of the Arctic and Antarctic poles.

Local legend says Isaac Newton built this footbridge without any screws, bolts, or nails.

An incredibly well-preserved piece of ninth-century Viking poop.

The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

Follow the original medieval paths that wind through this intriguing section of the city.

This network of narrow, medieval passages has the most delightful name.

One of the shortest streets in York has an especially odd name.

The little-known second castle that William the Conqueror built in York.

Largest tulip festival in America, includes fireworks, a parade, and a carnival.

Large-scale contemporary artworks tower over fields and lurk in forests around a Jacobean manor house.

Accessible only at low tide, the deserted island is dotted with World War II ruins.

This allegedly haunted 16th-century tower house-turned-museum exhibits thousands of spectacular objects.

This king penguin is a knighted brigadier of the Norwegian Army.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

A statue in the heart of Edinburgh honors a bear that served in the Polish military during World War II.