Largest illuminated advertisement sign in the world.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

Poland's oldest surviving university building holds a wealth of historic science instruments including some used by Copernicus.

Baroque celebration of the end of the Great Plague of Vienna.

The Habsburgs' royal collections of art and wonders.

The final resting place for the remains of 143 Habsburg royalty.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

The beautiful baroque library of the Hapsburg empire.

An underground city of salt.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

A sweet symbol marks the place where torturous executions were once carried out.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

A traditional U-Bahn station in Berlin gets a string of rather untraditional benches.

This classic restaurant features a gorgeous mirror-clad room.

A striking public sculpture representing the period of martial law in Communist Poland.

The silly symbol for an underground protest group is now scattered around the city.

A cluttered and astounding collection of antiquities and curiosities.

An abandoned Byzantine fortress and notorious prison.

360° views of the city plus five floors of optical illusions and hands-on science.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

Elaborate tile work in this railway station tells the story of Portugal.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”