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

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

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

The site of Paul Revere's historic two lantern warning.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

Dedicated to the European Sinti and Roma peoples murdered during the Holocaust.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Cold war icon and onetime "hole" in the iron curtain.

A restaurant and observation deck built in a unique broadcasting antenna.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The most visited, and possibly most controversial, museum in Germany.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Also known as the Temple of Poseidon, this is one of the best-preserved Greek temples in the world.

The first Italian factory to produce locomotives is now a marvelous museum.

A small town lost in the mountains of southern Italy hosts the childhood home of one of the most famous saints of the 20th century.

A galley-shaped memorial to the prisoners of an infamous fortress.

One of the earliest relics of Italian art is this ornately equipped stone soldier.

The tallest statue in Italy is also one of the world's tallest statues of Jesus.

One of the oldest and most significant collections of Ancient Egyptian archeology outside of Egypt.

This monumental fountain has moved around the city multiple times.