Authorities are gathering evidence and piecing together what led to the bridge collapse Tuesday in Baltimore. But so far, we know that Maryland Gov. Wes Moore said a large cargo ship lost power and issued a mayday call moments before it struck the Francis Scott Key Bridge. The span broke apart and tumbled into the Patapsco River almost instantly. Officials say six people are presumed dead and divers continue to search for them. They were in a construction crew filling potholes on the bridge at the time. Ship traffic has been suspended at the Port of Baltimore, which handles tens of billions of dollars in cargo each year.