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

One of the most ethnically diverse spots on the planet.

Looking for a unifying history, Uzbekistan finds its answer in a 14th Century Turco-Mongol conqueror... despite the fact he wasn't Uzbek.

Light still pours into the ruins of this ancient Islamic observatory.

The Avenue of Mausolea is a series of grand palatial tombs.

18m long sarcophagus of a constantly growing dead prophet.

This "tower of death" has acted as an observatory, a religious hub, and an executioner's lair.

Where Stoddart and Connolly suffered in the infamous Bug Pit.

The bears of Bern have been a city highlight for over 500 years.

Caves famous for the dragon-slaying saint who lived there.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

The tallest outdoor elevator in Europe rockets passengers on a dizzyingly precarious ride to the top of a mountain.

The world's longest outdoor covered escalator system transports commuters through Hong Kong's hilly terrain.

Teeming with illegal goods and services, this towering maze of vice is also a popular tourist accommodation.

Pablo Neruda's custom-built lover's nest was made to remind him of the sea and named after his mistress' hair.

A 125-meter long "tribute to the Brazilian people."

This massive Brazilian church is built like an angular, technicolor pyramid left by Mayans from the future.

The pedestrian traffic signals in Brazil's teeming metropolis light up with clues to nearby landmarks.

The bookstore with bookshelves built into unlikely places.

The design of the Palacio Salvo has been described as "a lighthouse on top of a building."

A blooming house of worship for the masses.

More than half of this Indian palace is drowned but it looks all the more spectacular for it.

The world's second-largest sundial, made entirely out of stone.