NPR News

Some 66 million years ago, about 75 percent of species on Earth disappeared. It wasn't just dinosaurs but most large mammals, fish, birds and plankton. Scientists have known this for a long time just from looking at the fossil record. If you dig deep enough, you find lots of dinosaur bones. And then a few layers up, they're gone.

But scientists couldn't figure out exactly what had caused this phenomenon. Of course, there were lots of theories.

The faces of American Kim Lee and her Chinese husband, Li Yang, both in their 40s, once graced the covers of books that sold in the millions. He was China's most famous English teacher, the "Crazy English" guru of China, who pioneered his own style of English teaching: pedagogy through shouted language, yelling to halls of thousands of students.

His methods were given official recognition after he was employed by the Beijing Olympic Organizing Committee to teach Olympic volunteers.

In 2009, a team of researchers from the British Antarctic Survey were studying satellite images of the Antarctic when they noticed something interesting: trails of penguin poop. That showed signs of a huge emperor penguin colony.

The existence of the colony was unconfirmed until a team of researchers from the International Polar Foundation visited in December 2012.