This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

The romantic garden was the epicenter of the Hungarian art scene in the 1880s.

Late at night, the bust of the "Dracula" actor was snuck onto the facade of this Budapest castle.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

A 13th-century convent where St. Margaret of Hungary spent her teenage years.

Legions of Roman soldiers bathed in this ancient spa complex under a Budapest transit station.

A random tree outside a Budapest hotel has become a DIY shrine to the late singer.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This easily overlooked memorial immortalizes the scars from the 1956 Hungarian Revolution.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

London's old-school healing garden.

The Art Deco artwork depicts gilded carriers of deadly illnesses.

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

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

An unassuming London park is actually a pilgrimage site for modern clowns.

A fully functional, 200-year-old remnant of the time when Brixton was mostly fields.

This may be the last of London's wooden pavements, which were once a common sight in the city.

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

The site of London’s first coffee house has been serving refreshments of one kind or another for 360 years.

Rebuilt remains of a temple to Roman god Mithras.