The only previous films to win five straight weekends in the past 20 years are 2009’s “Avatar” and 1999’s “The Sixth Sense.” “Titanic,” from 1997, holds the record, which seems unbreakable in the current quick-to-DVD era; it reigned for 15 straight weekends, according to Box Office Mojo. “Black Panther” is the year’s biggest release by a long shot, having grossed $605 million domestically and $1.18 billion worldwide.