A bit of the Berlin Wall was gifted to the Icelandic capital to commemorate the 25th anniversary of German reunification.

An encyclopedic collection of mammal penises.

The largest whale museum in Europe allows visitors to walk among life-size giants.

This beautiful example of Victorian engineering is the oldest water-balanced funicular anywhere in the world.

This tiny museum's sizable collection is jammed into a former underground public toilet.

A charmingly eccentric magma chaser presents his complete history of the island's eruptions since 1947, in cinematic form, just for you.

A quaint Russian village in the middle of a German metropolis.

More than 5,000 artifacts donated by the people of the city, plus a room entirely devoted to the band U2.

Though its celestial ceiling is impressive, the true star is the vast collection of French books.

A remarkably well preserved tower dating all the way back to the Iron Age.

An Industrial Revolution-era public work that purified water using nothing but sand.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

Amidst the bustling streets of Dublin, there is a hushed garden that is dedicated to "All those who gave their lives in the cause of Irish Freedom."

The modern birthplace of Irish freedom.

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

Some of the saint's blood and bones are said to reside in Dublin.

Wallabies live naturally on this Irish island.

A corkscrew-shaped barn in Ireland.

A strange egg in a mucky bog of western Ireland marks the spot of an aviation milestone.

Modern sundial uses ancient methods to tell time and date perfectly.

The oldest pub in Ireland may also be the oldest surviving bar in the entire world.

The oldest licensed distillery in Ireland.