A relic of World War I that now exist as a piece of public art.

Hungarian Jews were ghettoized during the Second World War, but little remains of the original wall that closed the Jewish people off from the rest of the city.

A giant glider—designed by the father of the Rubik's Cube's designer—now soars within a shopping mall.

The holes in this wall provide a glimpse into Jewish life in Budapest, both past and present.

From cartoon characters to tiny tanks, a guerilla sculptor's little bronze statues are hidden throughout the city of Budapest.

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

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

The ruins of an 11th-century Norman castle with a rare, perfectly circular shape.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

This mansion oasis contains gardens, sculptures, and fountains just off the busy Plaça Kennedy in Sant Gervasi.

This colorful statue welcomes visitors to a Barcelona park.

The unexpectedly beloved remnants of a controversial thermal power plant.

The former 1920s mansion of a prominent Catalan developer was used as the Soviet Embassy during the Spanish Civil War, and there is still a bunker below the garden.

A cemetery in Barcelona's Poblenou district is home to this touching funerary statue, which depicts death in the form of a winged skeleton.

Possibly the oldest church in Barcelona, this basilica has its pagan and Christian mythologies all mixed up.

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

Mountain where Jesus was first tempted by the Devil.

This cemetery features modernist statues as strange as its name.

A beautiful but toxic fountain of mercury.

A massive fallen water tank bombed by the Tamil Tigers in the final stages of the long Sri Lankan Civil War.

The "possessed" house that inspired "The Haunting in Connecticut" book and movie.

A memorial to a dog that inspired rioting in the streets of London.

Installed at a chaotic intersection, this gave London traffic cops a place to hang their heavy woolen coats.

This elaborate Byzantine-style building was designed for a not-so-pretty purpose.