A dreamy mausoleum honors Persia's most famous poet.

In this tiny Iranian town playing on the roof isn't just encouraged, it's the only place to go.

The fire inside this temple has burned for more than 1,500 years.

17th century mosque for Shah Abbas' harem.

A historic trade hub teeming with gorgeous architecture, colorful goods, and vibrant designs.

These little castles each held thousands of pigeons.

Modern-day cave dwellers carve elaborate homes out of volcanic debris.

This vast, water-filled underground labyrinth can only be toured by boat.

The ancient necropolis houses the immense rock-cut tombs of four Persian kings.

A sophisticated astronomical tower built by one of the greatest Persian scholars of the Islamic Golden Age.

This ruined fortress was the stronghold for a persecuted medieval leader and his infamous Assassins.

A 1,500-year-old, 3-story subterranean city where ancient Persians took refuge in times of war.

A spectacular rainbow of stained glass makes the "Pink Mosque" one of the most beautiful in Iran.

The palace of the King of Kings, burned by Alexander the Great.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

Macabre astrological automaton clock dating to the late 1400s.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

Breathtaking and huge 430 year old maps of Italy.

Russia's own leaning tower was built on a tragic historical fable.

Replica of mosque destroyed by Russia in the 16th century.

Inside the world's largest seed bank, WWII botanists elected to starve to death rather than compromise their collection.

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.