Explore the geological history of the Grand Canyon, one of the Seven Natural Wonders of the World.

FACT CHECK: We strive for accuracy and fairness. But if you see something that doesn't look right, contact us!

RELATED CONTENT

Explore the geological history of the Grand Canyon, one of the Seven Natural Wonders of the World.

Did you know that Grand Central is home to the largest Tiffany stained glass clock in the world? Host Brian Unger reveals the hidden history of Grand Central.

Grand Central Terminal is one of America's busiest train stations, with over 700,000 people passing through it every day. Find out more about this iconic landmark.

Did you know that there is a clock in the middle of Grand Central worth $20 million? Host Brian Unger reveals the hidden history of Grand Central Terminal.

Did you know that Hitler once sent spies to destroy the Grand Central train system? Host Brian Unger reveals the hidden history of the Grand Central underground.