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

A haunting collection of the vanished and disappearing natural world.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

Paris' linguistic guide to the international language of, yes, love.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

This museum houses an imposing skeleton army comprised of creatures great and small.

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

A series of abstract, silly sculptures represent the works of a great modern classical composer.

A beautiful Victorian statue shows France's enduring love of the rhinoceros.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

A quiet, semi-secret square with statues of Mahatma Gandhi, Virginia Woolf, and a conscientious objectors stone.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

The works of poetry's biggest names grace the walls of the city of Leiden, all carefully painted by hand.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

A 'living museum' in Leiden, the oldest of its kind in the Netherlands.

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

Take a stroll through the hellish grotesques of Hieronymus Bosch in this elaborate Netherlands church.

The world's largest grapevine has produced a delicious harvest at Hampton Court Palace for almost 250 years.

Built by crowdsourcing, this wooden foot bridge saved a part of Rotterdam that was languishing in wait of city funding.

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