These bronze pamphlets remember a remarkable group of Germans who fearlessly opposed the Nazis in the very center of their power.

This 19th century machine put animals (including humans) in boxes to study how they metabolized calories.

A small granite block at this monument's base is the only part of Lincoln's Tomb outside of Illinois.

Memorializing an American tragedy of massive proportions.

An 18th-century Catholic church converted into an eccentric temple of music and bacchanalia.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

The mortal remains of a Russian prince, priest and paranormal investigator who came to America in 1792.

An almost life-sized elephant named Ms. Ellie greets visitors at this jumbo-themed museum.

This dramatic rail curve was once the target of a failed Nazi attack.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

A local prank turned town icon.

This lush forest valley was once mined for lumber to the extent that it was once nicknamed "The Pennsylvania Desert."

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.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

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

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

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

In Florence's great Duomo, a 26 foot fresco honors a mercenary famous for attacking Florence.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

A sculpture serving as an homage to Pope John Paul II.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.