An icon of International Style architecture on the outskirts of Rotterdam.

The largest 19th century panorama in the world still in-situ.

Ship-sized kinetic sculptural fantasy.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

These murals stand as reminders to the troubled history of this Northern Ireland city.

A museum dedicated to the tragedy of Bloody Sunday.

A trail of "Game of Thrones"-themed doors carved from fallen trees from the iconic Dark Hedges.

Northern Ireland's Brobdingnagian stepping stones.

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

The ship built to ferry passengers and goods to the doomed Titanic is now the last remaining White Star Line vessel.

These engineering masterpieces are a dominant feature of the Belfast skyline.

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

France's national museum of scientific and industrial instruments.

One of its engravings is believed to be among the first representations of medical and surgical instruments.

These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.

The lost library of Alexandria, revived as a spearhead of cultural preservation.

Modest but unique pyramid built for a pharaoh has been reduced to a “heap of stone.”

This ancient structure is widely thought to be the oldest intact pyramid in the world.

The medieval center of the Islamic world was also once the seat of Saladin's sultanate.

In Egypt's expanding metro area, many of the neighbors are dead.

The home of half the world's population of critically endangered mountain gorillas.

Abandoned city hidden from the world by tropical forest and isolation on the coast of Kenya.

Kenya’s oldest town is more than 700 years old and home to 6,000 donkeys.

The world’s largest permanent desert lake is a UNESCO World Heritage Site.