This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

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

This World War II relic let Allied pilots know they were entering neutral airspace.

This beautiful site is where the first transatlantic telegraph was sent from.

Ireland's most remarkable collection of these curious cone-shaped houses is worth the buzz.

A proud bronze billy stands as an eternal symbol of Ireland's oldest festival, where a goat is made king.

Just a few miles off the western coast of Ireland lies an isle steeped in Irish literary history.

This ancient Irish tower could easily have stood in for Rapunzel's prison.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

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

The history and future of cannabis.

A student driver's nightmare.

Eighty million natural history specimens call this gargantuan museum home.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

A makeshift shrine to the late rock star is still kept up on the nondescript façade outside 1 Logan Place.

Pop culture has helped to keep this iconic British building from being destroyed.

This one has sailed five times as far as Sir Francis Drake's famous ship.

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

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

Originally built for London’s cab drivers, this bright green hut now serves anyone a hot drink or meal.

An exercise in radical design and social living that became the epicenter of Soviet spy networks in London.

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

A hugely vast Irish landscape of barren rock that stretches for miles.

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