China's president Xi Jinping arrives in Washington, D.C., for a two-day state visit. It comes as relations between the two countries are turbulent. Analysts say this will be President Obama's most difficult summit to date.
Seven hundred miles from the North Pole, there's an underground vault filled with seeds. It's sometimes called the Doomsday Vault. For the past few years, scientists have been filling it with samples of the crops that people rely on for food. Now, for the first time, they're about to bring some seeds back out. The reason? The war in Syria.
After the EPA said it found wide variations in emissions from VW cars that use a "defeat device" to fool emissions tests, the company's stock tanked, its CEO quit, and it's setting aside billions of euros to fix 11 million cars. So who made the discovery that sent the German car giant into a tailspin? A group of scientists at West Virginia University.