This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

An indoor miniature village and labor of love for Laurence Geiringer, a model railroad enthusiast.

In which a local geological marvel becomes a quaint roadside attraction.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Dr Barnes' $25 billion private collection of art and arboretum.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

A rare view of a preserved Victorian science museum.

A toxic ghost town sitting atop a massive coal fire.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

The world’s first penitentiary, meant to be humane, drove men insane.

The one-stop shop for all of your superhero (or evil arch-nemesis) needs.

A terrific purveyor of natural history objects and curios.

Few other hotels can rival the grandeur of the Castle in the Rockies.

Cathedral carved out of salt, located a mile below the Earth's surface.

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

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

If you've ever wanted to tear Hello Kitty apart with your teeth, this is the place.

This stunning concert hall has become a symbol of Iceland's national recovery.

Iceland: home to volcanoes, waterfalls and, apparently, Santa?

Theme park featuring miniature replicas of European monuments.

From Tintin to the Smurfs, Europe's greatest graphic icons are celebrated in a grand Art Noveau gallery.