Once America's tallest structure, now a Baltimore landmark.

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

This monument pays tribute to the city’s contribution to basketball history.

This Art Deco fortress in upstate New York gives Manhattan's vaunted examples of the style a run for their money.

Surprisingly aquamarine waters fill deep lakes formed at the end of the last ice age.

No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.

This column celebrates Rome's victory over the Goths, and may be the oldest Roman monument in Istanbul.

Ancient serpentine sacrifice holder that has stood the test of time.

A fountain standing as a testament to a doomed alliance.

1513 Turkish world map, full of European state secrets and snarky commentary.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

A marvel of Byzantine engineering under the streets of Istanbul.

Known as the Sistine Chapel of Egypt, this tomb houses some of the most well-preserved paintings in Egypt.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

One of its engravings is believed to be among the first representations of medical and surgical instruments.

The largest known Ancient Egyptian obelisk.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

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

Ozymandias’ time-keeping temple.

One of the most well-preserved temples of ancient Egypt.

An ancient instrument used to measure the waters of the Nile so Egyptian farmers would know whether to expect famine or flood.

The only arched bridge made of stone on the entire Mississippi River.

One of two giant blue cockerel statues erected with an intentional double meaning.