The remains of the dam that unleashed a 15-foot wall of water on Denver.

The first mountain submarine had its initial and last voyage in 1898.

One-time winter retreats of prolific inventor Thomas Edison and his friend Henry Ford.

Atop the former site of a historic bakery sit two stone tributes to Verona's contribution to traditional Italian baking.

A whale rib was used to advertise the store by the arch that offered exotic goods from far away.

One of the oldest libraries in the world is still operating and contains the oldest existing document in the Italian language.

This medieval castle was reconstructed by Carlo Scarpa.

A gorgeous example of 13th-century Gothic architecture.

Pilgrimage site for star-crossed lovers.

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

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

This unassuming cheese empire in rural Oregon churns out more than 150,000 pounds of cheese each day.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

A 200-year-old collection of oddities and medical paraphernalia.

A classic carnival ride that was carved to be untouchable.

This small section of the Sleepy Hollow Cemetery is rotten with famous authors' graves.

Louisa May Alcott based “Little Women” on her experiences growing up in this house with her sisters.

Oldest building in California still in use.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

One of the oldest used bookstores in the U.S. has been selling antiquarian treasures since 1825.

This kitsch eatery is chock-a-block with bric-a-brac.

This monument on Breed's Hill proves that one of the most famous battles of the Revolutionary War is misnamed.