How do you make a working human heart? Scientists can turn stem cells into beating heart cells, but getting them to organize into a 3D heart requires a scaffold. At the Massachusetts General Hospital in Boston, Harald Ott and his team are reusing the scaffold that nature provides. They're stripping...

Hundreds of thousands of students, parents, teachers and their supporters took to the streets on March 24, 2018 in a mass show of force in favor of gun control and school safety. More than 800 marches across the U.S. and around the world took place in support of the main March For Our Lives rally in