Every house has a few secrets. Maybe it’s a hidden reading nook beneath the stairs or a wine cellar behind a discrete door—or maybe it’s something a bit more dramatic. A new listing on Dairy Road in Greenwich, Conn. hits the mark for dramatic, as it comes with a secret underground tunnel that will make you feel like one of the agents from getting Smart. Except that, instead of leading to a really slick, top-secret HQ, it spits you out at a resort-worthy indoor pool.