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

This museum of Hawaiian and Polynesian culture is the legacy of the last descendant of the Kamehameha Dynasty.

A small storefront museum explores the history and myth of West Virginia's famous urban legend.

Once a speakeasy operated by Al Capone, this Milwaukee cigar bar is now a haven for ghost hunters.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

Despite many attempts to finish this overpass, it has been abandoned since the 1970s.

A giant roundabout made up of six smaller roundabouts can befuddle the uninitiated.

This bridge's unique architecture honors nautical heritage and encourages self-awareness.

An abandoned Ecuadorian prison that once held ex-presidents and notorious con artists is now a carceral museum.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

This statue was a gift to commemorate the Thai monarch's first visit to a foreign land.

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

When the Austin Dam failed it destroyed much of Austin...and then it failed again.

Abandoned bridge hidden deep in the San Gabriel Mountains.

At high tide this strange footbridge appears to have no purpose whatsoever.

An 18th-century Catholic church converted into an eccentric temple of music and bacchanalia.

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

A bike train runs along a disused railway line through the tranquil French countryside.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

Inspired by "The Starry Night" this Dutch bike path turns into a glowing work of art each night.

Hidden within a spa in a Texas strip mall is a restaurant specializing in Eastern European foods.

A small "palace" and museum made of, and devoted entirely, to salt.

In Paris, Texas they have their own Eiffel Tower, it just has a cowboy hat on it.

A classic gold rush hotel can be expected to pick up some ghosts along the way, and the Golden North is no exception.