The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

Every year model trains zip through a miniature New York City that's now 150 landmarks strong.

Rifle through images of skyscrapers, Worlds Fairs, and more in the largest public postcard repository in America.

A rare chance to get up close and personal with a 13-mile ribbon of ice near downtown Juneau.

This mysterious and creepy location instills a strong sense of foreboding in all visitors.

Hidden beyond a kitschy giant beetle is this remarkably sprawling collection of preserved insects.

Visitors to this library are in for a real-world education in modernist architecture.

A castle built for love, and abandoned due to heartbreak.

Mountain known by the Tillamook Tribe as "the place of the supreme deity."

Obscure Freemasons still live in D.C.’s largest private residence.

Display that gathers the basic elements of the universe in one convenient location.

This Rhode Island mansion was a stand-in for the exteriors of Collinwood in the original "Dark Shadows" series.

The only arched bridge made of stone on the entire Mississippi River.

Once the world's largest reinforced concrete structure, this abandoned bridge now beckons urban explorers.

An ornate Buddhist temple located in an Atlanta suburb, built by and for the Laotian community.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

Paranormal activity on the great lakes.

The oldest operating Mississippi River–style steamboat still navigates the Ohio River.

Doris Duke's lasting collection of Islamic Art, hidden in a Hawaiian paradise.

With over 340,000 artifacts and counting, there is something for everyone, often called the "Smithsonian of the West."

An extensive collection of fine art devoted to man's best friend.

This legendary urban waterfall creates a dazzling display of rainbows.

The largest retailer of seashells in the world.

With 3,000 bikes on display, the world's largest bicycle museum includes some famous rarities.