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

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

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

It took 28 years to build this massive statue of the Hindu god Vishnu riding a mythical bird.

Hindu temple of the dead home to hundreds of long-tailed macaques.

This massive complex is made up of hundreds of smaller temples that date back to the ninth century.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

For 60 years, the academy had no permanent location until members voted Washington D.C. as its forever home.

The "lovely red Vega" of the legendary record-settling pilot.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

The oldest continuously operating fish market in the United States.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

A painfully obvious spy house sits right across the street from the Russian Embassy.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

The Corinthian columns that towered over Abraham Lincoln’s inauguration stand proud.

This bewitching Babylonian goddess haunts a hallway of the British Museum.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

An architectural oddity hides in plain sight on this iconic London bridge.

A tiny replica of the iconic London landmark hides on the side of the steel structure.

A measuring mishap led to these artificial stone ladies losing their stomachs.

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

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

This long-hidden space above Westminster Abbey now displays the battle gear of the legendary King Henry V.