A stargazing sculpture made from the ruins of an iconic telescope.

With a surface area of nearly 500 square meters, welcome to the world's largest paraboloidal dish solar concentrator.

A castle hand-built by a Spanish dreamer in the Australian tropical jungle.

This historic hotel invented the chocolate brownie.

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

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

One of the largest free-standing structures ever built, this dirigible hangar is now simply a giant skeleton.

Since 1973, this block has been home to the most concentrated collection of murals in San Francisco.

Guns that have been defending San Francisco since 1904.

This private residence was the template for one of the most beloved television homes of all time.

An unexpected but incredible collection of wildlife dioramas spanning rainforests, swamps, forests, and plains.

"X" marks the spot of an echo chamber in the middle of a plaza.

An early-19th-century hotel with a past that is steeped in the Civil War.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.

Stuck in the arcade of Casa Isolani are three arrows of mysterious origins.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

Legend says this sacred tree was a gift from goddess Athena.

Qatar's oldest market can trace its origins back more than a century.

This 23-foot-tall bear stands amid the hustle and bustle of Hamad International Airport.

A museum dedicated to the history and exploration of both popular music and science fiction.

A wall of chewing gum moonlights as collective art.

The highest point in Washington state is a volcano covered in glaciers.