In this historic region, homes and churches are carved into ancient volcanic rock formations.

Once an indicator of social class, the color blue has come to define this city on the edge of the Thar Desert.

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

Iran's colorful terraces are a rare geological masterpiece.

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

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

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

This mesmerizing, colorful structure looks like a tent made from stained glass.

Get tall with nature's lankiest beasts and their warthog friends at this Kenyan preserve.

Drink and dine in a coral cave that's at least 120,000 years old.

Located in Nairobi National Park, this animal orphanage is the oldest of its kind in Kenya.

More than 100 monumental tombs carved into rock are preserved at this ancient Nabataean site in the Arabian Desert.

Museum housed in underground tunnels that date back to Buenos Aires's earliest settlements.

The inspiration for the Patagonia Clothing logo, Cerro Fitz Roy turns pink at sunrise.

This historic, palatial theater is now one of the world’s most beautiful bookstores.

This stunning mass of ice spans 121 square miles and is still growing.

In the most arid desert on the planet, the world's leading telescope allows astronomers to see more than has ever been seen before.

This observatory high on a hilltop in the center of Santiago got its start in 1852.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

This historic street in Quito is known for its seven stone crosses—and one presidential assassination.

A turquoise lake within a volcanic crater.

The explorer Captain Cook may have named it White Island, but the Maori call it Te Puia o Whakaari – The Dramatic Volcano.