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

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

An eccentric inventor's castle home with its own indoor weather system.

In the remote high desert of New Mexico, a strange array of poles beckon fury from above.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

The oldest hotel in the world has been operated by the same family for over 1,300 years, even catering to samurai.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

This lower Manhattan bar is set up in an old bank vault that rests beneath a skyscraper that hides even more historic splendor.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

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

A modernist landscape of water and sci-fi concrete.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

A marvel of Byzantine engineering under the streets of Istanbul.

A reproduction of earth's many biomes.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Each year these high desert hills are absolutely covered with poppy flowers in a surreal show of nature.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

The world's longest known cave system.