5 things to know for Dec. 15: Brown University shooting, Australia beach shooting, Rob Reiner death, Ukraine, JetBlue

CNN By Alexandra Banner, CNN Two cities, on opposite sides of the world, are united in mourning after deadly mass shootings over the weekend. In both cases, the attacks have left communities shattered while renewing contentious debates over gun control. Here’s what else you need to know to get up to speed and on with