This crucial gathering spot along the "hippie trail" still displays old notes between traveling beatniks and backpackers.

Step back in time and witness the fall of Constantinople.

The ornate miniature mansions were built for Istanbul's feathered residents.

No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.

The last remnants of a massive medieval wall that once encompassed the city of Berlin.

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

A diminutive, thousand-year-old church believed to be the smallest in Ireland.

The burial place of 14 of the executed leaders of the Easter Rising.

A retired military stronghold on the rolling green coast of Donegal.

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

This Neolithic passage tomb forms part of a World Heritage Site.

An oddly conical beacon perched atop beautiful Irish cliffs.

See some of the world's greatest racing horses at this idyllic thoroughbred breeding facility and garden complex.

This modest plaza in Moneygall, Ireland has cashed in on its distant connection to the U.S. president.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

After it was swallowed by a Georgian mansion, this medieval castle remained forgotten for centuries.

A particularly disconcerting tribute to Irish martyrs.

This 23-foot-tall bear stands amid the hustle and bustle of Hamad International Airport.

Theme park featuring miniature replicas of European monuments.

Climb inside an iron crystal magnified 165 billion times its normal size.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

A restaurant and observation deck built in a unique broadcasting antenna.

An abandoned train station in Munich constructed for the 1972 Olympic games.

Go surfing on this urban wave, "hacked" by local surfers.