There are hidden patterns on the subway seats of some Stockholm metro cars.

Finally reunited, the three effigies now stand in a museum courtyard.

This giant subway sculpture celebrates the fruit that inspired the theory of gravity.

Sound travels strangely in this underground whispering gallery.

Stockholm's deepest subway station is also a stunning ecological wonder.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Small Easter eggs are hidden in the ventilation holes of the city's newest trains.

There's something in the air as history repeats itself at this museum dedicated to the Swedish pop band.

The Swedish flag over this small naval fort signals that the nation is at peace.

It houses the remains of a 17th-century version of the Titanic.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

An enigmatic monument to the Irish revolutionary who plotted an uprising against British rule.

This neon landmark has been posing this deadpan question to follicly-challenged Dubliners for over 50 years.

The house where the writer spent his formative years.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This statue celebrating everyday life in Dublin has a few unsavory nicknames.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

The modern birthplace of Irish freedom.

Experience what life was like in Ireland during the Viking and medieval ages.

Legends surround an ancient tree trunk riddled with nails for good luck.

These two 15th-century metal rods allowed people to check if they were swindled or not.

A silly medieval mural preserved on the side of a Viennese house.

One of Vienna’s oldest (and perhaps most haunted) alleys, allegedly with a bloody past that gave it its name.