Though it's no longer a functioning train depot, this castle-like structure is an important piece of Oklahoma history.

This 19th-century prison once held Irish revolutionary Constance Markievicz, writer Frank O’Connor, and a nine-year-old pickpocket.

This ostentatious Italianate palace of an Oklahoma billionaire is filled with several themed mini-museums.

The only remaining sod house Oklahoma built by a homesteader in 1894.

A series of silhouettes that recall the great cattle drives of the 19th-century.

The world's largest anatomically accurate brain sculpture.

An eerie ship cemetery with gunfire as a soundtrack.

One of the largest private collections of fossils in the world.

One of Indiana's only natural sandstone arches is nestled between resort ruins and an old Boy Scouts camp.

The face of a woman pushes its way through the earth.

Former meatpacking facility turned vertical farm and sustainable business complex.

The beloved home to all publications indie, erotic, and punky.

Chicago's museum dedicated to the history of bondage and fetishism is more textbook than titillation.

This unauthorized stone mermaid was secretly carved out of public stone before being permanently preserved.

A lush green oasis in the middle of Chicago.

This morbid, delightful curiosity shop offers everything from animal bones to human teeth.

This former nursery supplied plants for the creation of Chicago's largest park.

The final resting place of the world's first nuclear reactor.

This museum is dedicated to preserving Minnesota's lake culture through displays of vintage watercraft and rotating exhibits.

Witness to many historic moments in early Texas history.

One-layer pyramid in Indiana.

Located in the place where the Columbia space shuttle came down, a museum-memorial that is both touching and informative.

The biggest depiction of Don Quixote's love interest in the whole world.

Built in 1981 in collaboration with Andy Warhol, this giant piece of pop art stands on the campus of Colorado State University.