"A hideous albatross in the Hudson River Valley."

The home of one of America's most wealthy industrialists is now a historic site that remembers a more decadent time in the country's history.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

The Hudson River School comes alive at this palatial estate.

One man's swirling six-acre monument of stone.

What was once a trend-setting, phrase-coining icon of architectural splendor is now a rotting, forgotten hulk.

The life of one of FDR's possible mistresses is preserved in her palatial Hudson Valley mansion.

One of the world's largest ice festivals dazzles visitors for over a month with radiant sculptures and carvings.

The final resting place for the remains of 143 Habsburg royalty.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

The largest self-built castle in the U.S., six decades in the making.

This once luxurious Catskills resort is now a haunting ruin.

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

Mysterious rocks that ring musically when struck.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

This ancient Irish religious site is covered in ancient carvings, many of which have barely aged.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.