In April, 2010 the eruption of Iceland's Eyjafjallají¶kull volcano turned much of Europe into an ash-strewn no-fly zone, stranding millions of travelers. But was Eyjafjallají¶kull just the start? Now, an even more threatening Icelandic volcano, Katla, has begun to swell and grumble. Two more giants, Hekla and Laki, could erupt without warning.

For Jet Propulsion Laboratory engineers, Curiosity's landing represented the culmination of many years of hard work and personal aspiration. In this video, they trace their love of space back to childhood memories and express their gratitude for being given the opportunity to land a rover on Mars.

Was Megastorm Sandy a freak combination of weather systems? Or are hurricanes increasing in intensity due to a warming climate? How did this perfect storm make search and rescue so dangerous? "Inside the Megastorm" takes viewers moment by moment through Sandy, its impacts, and the future of storm protection.

What caused the vast deforestation of Easter Island?

What makes an energy source renewable and how can we use them to power our societies?

The need for alternative energy sources is more pressing than ever.

A Greek shipwreck holds the remains of an intricate bronze machine that turns out to be the world’s first computer.

Modern wind turbines capture energy from the wind and convert it into electricity.

What can be done to make the power grid more reliable and efficient?

How can we convert the Sun’s light and heat into energy we can use?

What is energy and why are we on a never ending search for new energy sources?

A remote, bleak speck of rock in the middle of the Pacific, Easter Island, or Rapa Nui, has mystified the world ever since the first Europeans arrived in 1722. How and why did the ancient islanders build and move nearly 900 giant statues or moai, weighing up to 86 tons? And how did they transform a presumed paradise into a treeless wasteland, bringing ruin upon their island and themselves?

The Vikings were among the fiercest warriors of all time. Yet only a select few carried the ultimate weapon of their era: the feared Ulfberht sword. Fashioned using a process that would remain unknown to the Vikings' rivals for centuries, the Ulfberht was a revolutionary high-tech tool as well as a work of art. Considered one of the greatest swords ever made, it remains a fearsome weapon.

Airing October 17, 2012 at 9 pm on PBS

Witness the exhilarating moments of Curiosity’s Mars landing — and the spectacular discoveries afterward.

Watch an uncut interview with the late astronaut, conducted at NASA in 1984.

Go behind the scenes at CERN for exclusive interviews with lead scientists on the historic July 4 announcement.

Find out how an airliner with elaborate safety and navigation features and a faultless safety record could simply vanish. 6/13/2012

Take a safe front-row seat to the risky and thrilling art of chasing twisters. 5/9/2012

It contains 99.9 percent of all the matter in our solar system and sheds hot plasma at nearly a million miles an hour. The temperature at its core is a staggering 27 million degrees Fahrenheit. It convulses, it blazes, it sings. You know it as the sun. Scientists know it as one of the most amazing physics laboratories in the universe.