Monasteries on rock pillars, once accessible only by frayed ropes.

Climb atop one of the world's longest and heaviest trains for an unbelievable journey across the Sahara Desert.

Five ancient libraries, little changed for centuries, preserve a medieval archive of Quranic lore and civic documents

An architectural relic that survived the hands of time.

This architecturally eclectic early-20th century mosque was built as a place of worship for the Islamic followers of a Jewish messiah.

An abandoned Byzantine fortress and notorious prison.

One of the most photographed locations in the entire city.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

Gargoyle head that brings good luck.

An ancient knight and a symbol of the city's freedom.

Longest fortress system anywhere in Europe.

The big toe of this towering monument to a Croatian national hero is worn from years of superstitious rubbing.

Home to the oldest operating roller coaster in the Southern Hemisphere.

The heads of two giant mythological water horses honor Scotland's horselord past.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

A mesmerizing reservoir nestled at the heart of a pre-Islamic Yemeni village.

Yemen's "Stone Palace" looks like it was carved right out of the tall stone column on which it is built.

Elaborate patterns adorn the city's disappearing traditional architecture.

The ancient abodes are a testament to human ingenuity amid harsh climates.

Mausoleum and Holy Seat of Antiochus I of Commagene.

Balanced on four stone pillars, this historic tower was the site of a tragic political assassination.

This ancient city - home to nine civilizations - is soon to be buried under 200 feet of water.

Unique pagan culture in three extremely remote mountain valleys.

This ancient Silk Road outpost overlooking the Wakhan Valley is miraculously still standing.