The headquarters of the famous Yale society.

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

This "thrice-cursed" island is allegedly home to Captain Kidd's lost treasure.

Quirky castle designed by the American actor best known for portraying Sherlock Holmes on stage.

An archival collection of over 2,200 case studies which includes human brain specimens and tumor specimens.

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

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

Legends surround an ancient tree trunk riddled with nails for good luck.

A spherical "micro-nation" in the heart of Vienna.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Located right outside of Vienna, visitors can take in expansive views of an ethereal forest.

Once the home of a hermetic monk, this cave now houses a small church.

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

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

This statue of a falling man commemorates a teenage martyr of the Hungarian Revolution.

A museum in the childhood house of a medical pioneer.

A random tree outside a Budapest hotel has become a DIY shrine to the late singer.

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

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

This Transylvanian church has changed its denomination four times.

Romania's "Red Ravine" is a little-known natural wonder that bears a resemblance to the Grand Canyon.

Something's watching you.