Fire meets ice at the southernmost volcano on Earth.

Iran's colorful terraces are a rare geological masterpiece.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

A lake in the middle of the tundra of Quebec is said to be the purest freshwater lake on Earth.

A lake formed in the basin of a massive impact crater takes the shape of an unbroken ring when viewed from above.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

Comprehensive gaming collection of over 30,000 electronic games and consoles.

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.

The palatial McDonald's that inspired Wesley Willis.

A century-old network of freight tunnels underneath the city's historic business district.

A Museum of Holography frozen in 1974.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

One of the largest and oldest caravansaries in Persia.

This vertical pinnacle in China was the inspiration for the floating mountains in the movie “Avatar.”

Rock-cut caves and 7,000 Buddhist sculptures carved into the nearly sheer face of a sandstone mountain.

This temple located on a vertical drop of a rocky mountain houses relics from the Song Dynasty.

Abandoned rock quarry now a haven for mountain bikers and hikers.

This quiet area of Yunnan Province annually transforms into an unbelievable sea of yellow flowers.