This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

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

The former home of Samuel Clemens and family remembers the happiest period of the author's life.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

A restored Pittsburgh house of God has been converted to a marvelous house of suds.

The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.

An architect's childhood fantasy treehouse made real.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

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

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

A geological mystery on Camelback Mountain.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

The land is home to swimming ponies and a legendary 18th-century treasure.

Elvis's own personal tropical hideaway.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

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.

A crumbling hospital from the 1850s on Roosevelt Island.

Experience a charming 1930's version of "infotainment."

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

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

London's smallest police station is barely the size of a phone booth.

Every day a troupe of pampered water fowl walk the red carpet to their favorite fountain.

The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.