An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

This imposing memorial contains the remains of Che Guevara — and 29 other guerrillas who died with him in Bolivia.

Neo-cave art on the macro scale.

Once a favorite playground for the world's most illustrious guests, Hotel Nacional's secret weapons and bunkers reveal a more menacing side to its golden history.

A focal point of the Cuban government, this city square features one of the most iconic images in the country.

A Cuban artist reclaimed his impoverished neighborhood as a dreamy folk art kingdom.

Thailand's distressed elephants find peace at this Chiang Mai sanctuary.

Only through deep darkness and tragedy did this elaborate royal palace become a sacred temple.

An underwater restaurant, surrounded by a coral reef.

Colorful umbrella-covered trees in Singapore's Little India look straight out of Dr. Seuss.

This statue once earned the distinction as one of the "Three Major Disappointments of the World."

This museum covers 10,000 years of Pre-Columbian Latin American history.

No building in the world leans as far as the so-called “Leaning Tower of Abu Dhabi.”

The world's largest frame offers spectacular views of the city's past and present.

On any given day this sprawling market houses literally tons of government-regulated gold, gems, and precious metals.

A preposterously luxurious hotel with gold-plated iPads, Rolls Royce chauffeurs, and a staff that trains by watching "Downton Abbey."

This indoor ski resort has a mountain contained inside a mall.

This artificial archipelago was supposed to resemble a map of the world.

Also known as the "Red Taj Mahal."

Many Hindus make the long pilgrimage to this holy city to have their remains burned on the banks of the Ganges River.

This Gothic-style church is reputedly built atop the remains of one of Jesus's apostles.

The second-longest continuous wall on the planet protects a hidden secret in the deserts of India.