How can you tell two species apart? It’s not always simple. In this episode of Crash Course Biology, we’ll learn about speciation—a process that can happen over millions of years, or within a single generation. Along the way, we’ll...

High elevations can be a problem for humans. Since the air is thinner, you get less oxygen with every breath, leading to all kinds of negative side effects. But there are millions of people around the world who spend their whole lives at...

As soon as Pharaoh Khufu ascended the throne circa 2575 BCE, work on his eternal resting place began. The structure's architect, Hemiunu, determined he would need 20 years to finish the royal tomb. But what he could not predict was that...

High elevations can be a problem for humans. Since the air is thinner, you get less oxygen with every breath, leading to all kinds of negative side effects. But there are millions of people around the world who spend their whole lives at...

North America didn't always have its familiar shape, nor its famed mountains, canyons, and plains: all of that was once contained in an unrecognizable mass, buried deep in Rodinia, a huge supercontinent that lay on the face of the Earth....

If you look out your window, you'll probably notice a bunch of things; houses, streets... hopefully a tree. But beyond that you'll see things like mountains, rivers, volcanoes... well, hopefully not a volcano. These are landforms and...

Howcast - Learn how to do the preacher curl using a Swiss ball from personal trainer Brett Azar in this Howcast home arm workout for men video.

Howcast - You will see a difference in your weight-loss with these simple lifestyle changes.

Due to introduced predators, disease, and habitat destruction, they are almost out of time. See what other challenges the team faces.

Due to introduced predators, disease, and habitat destruction, they are almost out of time. See what other challenges the team faces.

Due to introduced predators, disease, and habitat destruction, they are almost out of time. See what other challenges the team faces.

Due to introduced predators, disease, and habitat destruction, they are almost out of time. See what other challenges the team faces.

Deep into the Alaka'i plateau on the island of Kauai, two species of birds are rapidly nearing extinction, with only a few nests remaining in the wild.

Due to introduced predators, disease, and habitat destruction, they are almost out of time. See what other challenges the team faces.

Due to introduced predators, disease, and habitat destruction, they are almost out of time. See what other challenges the team faces.

Deep into the Alaka'i plateau on the island of Kauai, two species of birds are rapidly nearing extinction, with only a few nests remaining in the wild.

Due to introduced predators, disease, and habitat destruction, they are almost out of time. See what other challenges the team faces.

Due to introduced predators, disease, and habitat destruction, they are almost out of time. See what other challenges the team faces.

Landforms are natural features on Earth's surface. They come in all shapes and sizes. In this video, learn about the different landforms found in the United States.

PYRAMIDS THEY'RE ONE OF THE HISTORY S MOST ENDURING LANDMARKS, AND A MUST-SEE ATTRACTION FOR TRAVELLERS TO EGYPT. EVERY YEAR THOUSANDS OF VISITORS FLOCK TO SEE THE PYRAMIDS NEAR CAIRO. THE SITE CONTAINS THE GREAT PYRAMID OF KHUFU, THE...

Liverpool, United Kingdom:"We’ll go to the United Kingdom, to the cradle and home of one of the most famous bands in the world, The Beatles. We will be in the fantastic city of Liverpool; which also has a legendary football club. There...

Learn how the Colorado River carved this incredible land formation, revealing nearly two billion years of the Earth's geological history in the process. Earth Science - Geology - Learning Points. The Grand Canyon is a gorge 2km deep,...

Learn how our planet's landscapes, from mountains to hills, plateaus to plains, have been sculpted over millions of years by powerful geological forces. Earth Science - Geology - Learning Points. The planet's diverse landscape is shaped...

This video dives into two of Earth's most magnificent water-based natural wonders. Discover the vibrant marine life of the Great Barrier Reef, the world's largest coral reef system, and learn about the challenges it faces due to...