Bodies of water are frequent metaphors in poetry due to their unfathomable depths, unknowable sprawl, and unattainable porpoises. Set sail into the enigma with today's Groupon: for $20, you get two tickets to the Victory Rover naval-base cruise in Norfolk (up to a $40 value).

Atop the Victory Rover, guests absorb the oceanic sights and sounds of the naval base, replete with aircraft carriers, nuclear submarines, and other armada accouterments illuminated by a boat-top docent. Up to 149 guests can feast eyes on the gentle waves of the Elizabeth River and Hampton Roads Harbor as their buoyant steed maneuvers past huge commercial ships and giant rubber duckies. On two-hour tours scheduled almost daily, the Victory Rover traverses a cruise route that takes history buffs past the site of the Civil War Battle of the Ironclads and mythology buffs past Poseidon’s watery front lawn. A main cabin stocked with plush seats and air conditioning offers respite from the salty breezes and talkative parrots of the otherwise comfortable open-air top deck.