The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

France's national museum of scientific and industrial instruments.

Apartment complexes built into huge repurposed natural gas tanks.

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

Romania's triumphal arch looks out over Bucharest.

This museum is dedicated to the most famous Irish writers in history.

The world's only flying boat museum honors a small Irish village that sent 20th-century aviation to new heights.

These caves secretly held national treasures during World War II.

The abandoned "Red Star Train Graveyard" is the final rusting place for precious artifacts of train history.

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

In a divided Germany, Potsdam's "central" train station was relocated to the city's southern suburbs to avoid West Berlin.

This mine is home to the largest man-made hole in Europe.

This concrete residential area doubles as an open-air gallery.

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

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

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

This charming railway is one of the oldest and steepest funiculars in England.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This "floating railway" is one of the world's oldest monorail systems.

Cold war icon and onetime "hole" in the iron curtain.

A unique hanging cable-car navigates through Dresden, the oldest suspension railway in the world.

This small train ride offers stellar views of the Grand Garden Palace.

The abandoned transportation hub hides within the Glasgow attraction it once served.