Biggest group sex orgy video

500 people, 250 couples, having sex in a Japanese movie.
It features 250 couples, described by SOD as students, who enter what looks like a large warehouse, and over the course of two hours, engage in a variety of foreplay, mutual masturbation, and intercourse. All sexual acts are performed in near synchronization with all the other couples.
Unlike a typical orgy or swingers' party, each couple has sex only with themselves, and no other couple.
The 130 minute video, was produced by in-house production company SODcreate, and directed by Tsuchiya Yukitsugu (土屋幸嗣).
Video Source (including promotional pictures and screengrabs)