Baltimore's classic clock tower was once topped by a rotating, 20-ton medicine bottle.

A preserved oasis with traditional Andalusian-style architecture and beautiful views of the Nile.

These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

An ancient Egyptian obelisk is now used to commemorate fallen Italian soldiers.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

This small Roman arch was transformed into a dwelling by the founder of the Trinitarian Order.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

The commemorative stone column conceals a secret laboratory.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

One part local history, 99 parts gruesome haunted house.

Nine bronze hands protruding from a wall honor the student uprising that led to the fall of Czechoslovakia's Communist government.

Steadily reminding Czechia of its past.

A series of playful yellow penguins share a serious message about the environment.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Macabre astrological automaton clock dating to the late 1400s.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

An underground city of salt.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

In the midst of a living monument to Soviet social engineering, Polish Catholics built this church by hand.

One of the most poignant ruins of the Chornobyl nuclear disaster, the local football team's stadium has been quickly reclaimed by nature.

This derelict superstructure was a very important warning system for the Soviet military.

This underground transport hub doubles as an art gallery.