Hands across the DMZ, activists urge Facebook to change and when whale songs go viral

Today, we'll tell you all about today's historic summit between the leaders of North and South Korea, and find out what's left to negotiate if President Donald Trump meets Kim Jong-un. Also, activists in Myanmar and Sri Lanka are pushing Facebook to take down hateful content before there's real world violence. And, our language desk tries to figure out how the sounds of whales travel from one pod to another across vast swaths of ocean.