Rooftop Films is known for presenting “underground movies outdoors” at offbeat and unusual locations throughout New York City, but on December 11-12, they’ll literally be showing underground films underground as they head beneath the streets of Brooklyn and into the amazing Atlantic Ave. tunnel. Built in 1844 and rediscovered in 1980 by Bob Diamond, who has been leading tours of the landmarked site for many years, the tunnel, which was added to the National Register of Historic Places in 1989, offers a unique experience to those who love trains as well as those seeking access to New York’s hidden treasures. On both days, Diamond will first lead a tour before the films begin. On the schedule for Saturday afternoon’s Trapped in the Tunnel program are Robert Glickert’s ROAD TO MOLOCH, Matt Palmer’s DAYLIGHT HOLE, Eric Scherbarth’s SINKHOLE, Emily Carmichael’s LEDO AND IX GO TO TOWN, Nathan Kensinger and Meghan O’Hara’s COVERED TRACKS, and S. Vollie Osborn’s MONSTERS DOWN THE HALL, while Sunday’s Tunnel of Love lineup consists of Sean Durkin’s MARY LAST SEEN, Carter Smith’s BUGCRUSH, Bobby Miller’s TUB, and Yohan Guignard’s STRATES. Tarps for seating will be provided, or you can bring your own small cushion, but no food or drink is allowed in the tunnel, and there are no bathrooms either; you can take care of some of those needs at the official after-party at Last Exit, which will feature complimentary spiced rum drinks courtesy of Sailor Jerry. And if you’re afraid of confined spaces, ladders, and the dark, you might want to think twice before buying a ticket or else be ready to battle your phobias at what should be a pair of awesome events.