Like a tarp thrown over a '67 Mustang, the placid surface of the sea on a fine day conceals a whole bunch of sharks. Ride down the world's watery highways with today's Groupon: for $8, you get two admission tickets to Atlantic City Aquarium in Historic Gardner's Basin Waterfront Park (up to a $16 value).

Supplied with more than 30,000 gallons of seawater, Atlantic City Aquarium showcases more than 100 varieties of marine life. A plethora of abyssal exhibits take explorers into underwater lands, allowing them to peer into the natural habitats of endangered diamond-back terrapins and intimidating sharp-toothed piranhas, or have a glance at what a clown fish does when not constructing balloon plankton. A tank of the ocean's oddities offers a glimpse at unusual nautical fauna, such as the deadly stonefish, which exemplify nature's infinite variety and bizarre adaptations. On the aquarium's shores, the tropical rainforest and exotic animal show provide a genuine zoological experience completely free from high-heels and feather boas.

As interactive as it is educational, the Atlantic City Aquarium offers 20-minute Dive and Dine feeding shows, wherein the aquarium's diver hand feeds cownose rays and takes swimming lessons from nurse sharks while dogfish patrol the perimeters. Question-and-answer sessions follow each show. A 900-gallon touch tank exhibit lets visitors get friendly and hands-on with formerly elusive nonmammals, including smooth juvenile stingrays, playful sharks, and horseshoe crabs, the only arthropods that double as good-luck charms.