While Grand Cayman’s waters harbor legendary coral reefs, there’s another treasure waiting to be discovered below the surface in a marine park off Seven Mile Beach. About 60 feet down rests the intentionally submerged Kittiwake, a historic U.S. Navy rescue ship renowned for—among other feats—finding the long-sought black box from the space shuttle Challenger disaster in 1986. Whether you’re snorkeling above the vessel’s smokestack and main decks or diving into the engine rooms, decompression chambers, captain’s bridge, showers, bathrooms, galley, and crew quarters, the 251-foot Kittiwake makes for a surreal outing. Among other denizens, barracuda, garden eels, horse-eye jacks, and the occasional nurse shark await you there.