Khmer Rouge's high security prison.

The 28-foot granite map plots the locations of 40 theaters in New York City.

The elegant structure of this 19th century railroad bridge creates an illusion of infinity.

The building's fluid, wavelike walls are a true feat of architectural ingenuity.

This futuristic building is yet another architectural wonder in Dubai.

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

This opulent 16th-century Maharaja’s palace is a unique mix of Hindu and Muslim designs.

An ancient wall in the shadows of the Amber Castle.

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

The 953 windows undoubtedly make this the world's most beautiful screened porch.

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

An imperial fortress city that incorporated cultural elements from the entire Mughal empire, only to be abandoned the year it was finished.

Also known as the "Red Taj Mahal."

A blooming house of worship for the masses.

An ancient iron pillar in Delhi that seems to be rustproof.

The mysterious empty cupola behind the monumental arch points to an ancient prophecy of Delhi.

A weekly bazaar sells thousands of books, from vintage collectibles to paperbacks sold by weight.

A unique museum dedicated to culture and artistry of carpet weaving.

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

A gigantic collection of teeny, tiny books.

This mysterious but iconic tapered tower appears in many Azeri fairytales and legends.

A sculpted indigenous garden featuring more than 60 works by Dylan Lewis.

These 250-year-old wagon tracks are a lasting sign of Dutch migrants crossing the mountains.

Controversially restored in the 1970s, this giant 15th-century mosque is shrouded in legend.