A scattered trail of street art adds a pop of color to the city's stark structures.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

One of the few surviving examples of Victorian-era public toilets now houses a small homestay.

This restaurant was removed from the famed sister ship of the Titanic and placed within a hotel.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

This building has survived for more than a century and remains virtually untouched.

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

One of the most easily accessible examples of the rare 1960s UFO houses.

Go surfing on this urban wave, "hacked" by local surfers.

One of Antoni Gaudí’s earliest buildings, built between 1886 and 1890 for the industrialist Eusebi Güell.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

A beautiful but toxic fountain of mercury.

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.

Started as a kitchen garden, now the second largest botanical garden in the world.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

The most visited, and possibly most controversial, museum in Germany.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

From toys to kettles to scientific instruments, this German museum celebrates the beauty of 20th century design.