Genesis of modern hydroelectric power.

Toxic waste disaster that founded the Superfund program.

Created by four famous men, the beautifully designed Buffalo State Asylum was resurrected as a hotel and art center, but still boasts a ghost story or two.

A monument honoring those who died in the Great Famine of Ireland.

This restored house is like a time capsule of the president's unconventional inauguration.

A monument to a Polish general who fought the American Revolution and became the "Father of the American Cavalry."

More than 350 million years ago, western New York was covered in a vast sea. Today, you can dig up the remains of the plants and animals that lived there.

The Vermont grave of a 4,000-year-old mummy prince.

A wonderful display of arts and crafts handmade by local artisans in the Southern Appalachians.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

Two stone columns flank the grand Venice square, but there were supposed to be three.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

Go inside to really appreciate this 500-year-old technological masterpiece.

Carved fountains poignantly placed in parks and in front of special monuments.

This quiet, unassuming spot in Budapest was the birthplace of the bloody 1956 Hungarian Revolution.

This easily overlooked memorial immortalizes the scars from the 1956 Hungarian Revolution.

Late at night, the bust of the "Dracula" actor was snuck onto the facade of this Budapest castle.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

The unusual sculptures are believed to be powerful political symbols.

In the hinterlands of Serbia's capital, a giant reflective mushroom houses an aeronautical history of the former Yugoslav republic.

A misnamed well, with a deep dark past.

The ruins of this medieval castle on a foggy hill tell the story of a once-mighty empire.