The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

The fierce beast perches atop a pedestal marking where the historic City of London gates once stood.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

Its collection includes a broad array of social, geographic, graphic design, and political history.

A mysterious shape catches the eye in this 16th-century painting.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

London's smallest police station is barely the size of a phone booth.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

These ornate arches show how the course of the River Thames has changed.

The medieval woodcut-style artwork chronicles life in medieval London.

Avoid gangster interaction while window-shopping.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

The most confusing clock in New York.

A 19th-century politician who died after walking home in a blizzard is honored with this Manhattan statue.

Elevated freight railway turned wildly successful urban park.

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

The Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.

A propulsion engine testbed that paved the way for the Space Shuttle launch sits without recognition at this rocket center.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

The library's graceful rotunda is like a bibliophile's temple.

Stockholm's deepest subway station is also a stunning ecological wonder.

The scars of a remarkably organized public protest to save 13 elm trees are still visible in this Stockholm park.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.