Discover what the relics of an oasis reveal about the fall of the civilization that built Petra.

See how the majestic stadium looked 1,900 years ago.

The arena where gladiators trained, and how they made their grand entrance into the Colosseum.

Despite being in a Hindu country, the Taj features a great deal of Muslim symbolism.

See inside the famous Indian monument as never before.

Travel deep into the chambers of the Egyptian mega-temple to find a hidden city and uncover its mummies.

The truth behind Karnak's hypostyle wall, where Ramses II covered up the work of his father, Seti I.

Each warrior in Emperor Qin Shi Huang's Terracotta Army is unique. Here's an inside look at how the army was built.

Archaeologists believe the body of China’s first emperor, Qin Shi Huang, lies in a mysterious underground burial complex.

More than 170 skeletons are buried under Machu Picchu -- what do their deformities say about the mysterious city?

The ancient Incan civilization used quipus, or knotted cords, to keep records.

Witness the grandeur of Stirling Castle and learn about the unexpected guests buried just below it.

Scotland's Stirling Castle is linked to the adventures of two larger-than-life heroes.

Tour the most famous prehistoric monument in the world, and discover the graves that lie below.

A 600-year-old French manuscript reveals clues tying King Arthur to Stirling Castle.

Clues reveal what the Sphinx Temple looked like more than 4,000 years ago, and its secret ties to the yearly equinoxes.

See inside the famous Indian monument as never before.

Despite being in a Hindu country, the Taj features a great deal of Muslim symbolism.

See how the majestic stadium looked 1,900 years ago.

The arena where gladiators trained, and how they made their grand entrance into the Colosseum.

Discover what the relics of an oasis reveal about the fall of the civilization that built Petra.

Supermassive black holes aren't just spinning at the center of galaxies. They may actually be creating galaxies.

Stripping away the Milky Way's stars, planets, rocks and dust reveals a massive black hole lurking just 26,000 light years from Earth.

Astronaut Mike Massimino calls solar wind, "the biggest obstacle we have for exploring our universe."

More than 20 solar storms a day can occur on the surface of the sun. These energy surges can cause real problems down on Earth.

The dinosaurs died off after a massive asteroid strike with a billion times more energy than the atomic bombs dropped on Hiroshima. A team at NASA studies the impact to learn more.

In February 2013, a stunning sight in the sky over Russia made international headlines. The light of an asteroid hurtling toward Earth was brighter than the sun.

Scientists are studying Mars from every angle in preparation to send the first human astronauts to the Red Planet. Data from the Curiosity rover has proven invaluable.

Mars is home to Olympus Mons, the largest volcano in the solar system, which covers an area the size of Arizona.

Saturn's tiny, frozen moon Enceladus could hold the secrets to extraterrestrial life.

Titan, the largest moon of Saturn, could be the most alien world in our solar system.

On March 24, 1967, men see an unidentified object hovering over Montana’s Malmstrom Air Force Base, home to nuclear weapons, which are all disabled simultaneously.