Murals of the wild parties once held on the frozen River Thames.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

The library houses an incredible collection of some of the world's most impressive books and manuscripts.

Britain's answer to the NSA is based out of this deliciously-named circular headquarters.

A pub that claims a lineage as one of England's oldest inns, back to 947 AD

Built for herding sheep, these tiny winding lanes with medieval origins and distinctive series of narrow turns are charming walkways for humans today.

This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.

A forgotten "city of water" underneath the famous Trevi district.

Krakow's own version of the Hollywood Walk of Fame.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Learn the fine art of making a centuries-old treat at this hands-on food museum.

Remnants from a time before electricity.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.

A statue commemorating a Polish dog who took his role as man's best friend very seriously.

Extremely famous in his native country, this Cracovian painter is all but unknown beyond Polish borders.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

Legend holds that this knife serves as a chilling reminder of the deadly rivalry between two local builder brothers.

In this quiet village, a blue plaque marks the spot where the famous fictional detective retired.

This sprawling, Brutalist estate feels like a city within a city.

The world’s second-largest flood defense barrier has protected London for decades.

A defensive structure built during the Hundred Years War has remained useful in one way or another for nearly 700 years.

This skewed English house has looked like it's going to fall over for centuries.