The celebrated eyesore created by starry-eyed sweethearts.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This massive library holds what was once the largest book collection in the world.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The only monument to name all of the passengers and crew who died on the RMS Titanic.

A small plaque highlights the damage caused by German air raids during World War II.

For part of the year, this innovative greenhouse is painted white to keep the plants from getting scorched.

Celebrated in poem, this tiny hidden cemetery has a big and grisly history.

It was once nicknamed "the most bombed hotel in Europe."

These barriers stand as stark reminders of Northern Ireland's troubled past.

Belfast's namesake river still winds below the city center, hidden from sight.

An Irish cemetery filled with victims of political strife and violent conflict, including the grave of Bobby Sands.

A palatial former bank building now houses what may be the poshest art venue (and former Tesco) in Belfast.

A museum marks and documents the site of the Titanic's launch.

This Victorian-era public house has set the standard for pub-style elegance for over a hundred years.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.