Brett Reinke

Wildlife photographer Steve Winter and cameraman Bertie Gregory capture the lives of jaguars in the Pantanal of Brazil; a mother jaguar teaches her cub how to survive, while a male jaguar dives headfirst into a river to tackle a six-foot-long caiman.

What animals do when they think no one is watching.

The tornado that struck El Reno, Oklahoma, on May 31, 2013, defined superlatives. It was the largest twister ever recorded on Earth.

On a summer's night, there's nothing more magic than watching the soft glow of fireflies switching on and off. Few other life forms on land can light up the night, but in the dark depths of the oceans, it's a different story: nearly 90% of all species shine from within. Whether it's to scare off predators, fish for prey, or lure a mate, the language of light is everywhere in the ocean depths, and scientists are finally starting to decode it.

Around 800 BC, Kush, a little-known subject state of Egypt, rose up and conquered the Egyptians, enthroned its own Pharaohs, and ruled over the empire of King Tut for nearly 100 years. This unlikely chapter of history has been buried by the Egyptians and belittled by early archaeologists, who refused to believe that dark skinned Africans could have risen so high. But now, in the heart of Sudan, archeologists Geoff Emberling and Tim Kendall are bringing the truth about the Black Pharaohs to life.

The Vikings were the most ferocious warriors of the Middle Ages. Especially fearsome were the select few who wielded a formidable weapon: a light, razor sharp, virtually indestructible sword with its maker's name, Ulfberht, inlaid along the blade.