A magnificent, glittering building tucked into a tiny Bulgarian mountain town.

The site of many battles and tragedies, including the 40 maidens who leapt into the sea.

The Great Fire of London and the regulation of one-way streets both started in this alley.

Artists and musicians now rule over this former rail station.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Notorious artist squat renovated into legal studios.

France's most famous cemetery, with some of its most curious tombs.

Dine amidst exotic plants at this former royal greenhouse.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Op-art architecture designed for happiness.

A spherical "micro-nation" in the heart of Vienna.

Berlin's old airport.

Floating swimming pool within a moored vessel.

Blitzkrieg bop your way through Berlin's Ramones Museum.

Super-heavy Nazi architectural experiment.

A fascinating insight into daily life in the Eastern Bloc.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.