Avatar broke box-office records yet again this weekend and became the fifth movie ever to bring in more than $1 billion in ticket sales worldwide. “This is like a freight train out of control,” said one Fox executive. “It just keeps going.” The film surpassed The Dark Knight worldwide, and is nearing on Batman’s domestic box-office record of $533 million. Coming in second place with only a modest drop in sales was Sherlock Holmes, which took in $38.4 million. Family-friendly Alvin and the Chipmunks: The Squeakquel took in $36.6 million during the holiday that saw no major releases and followed up last week’s record-breaking Christmas haul.