Until the invention of scuba diving, swimmers who wanted to see the ocean floor had to rely on unwieldy 100-foot-long snorkels. Celebrate unfettered exploration with today's Groupon: for $225, you get a PADI open-water online course course (a $120 value), plus a pool session and four open-water dives (a $349 value) from Divers Discount Florida (a $469 total value).

Divers Discount Florida equips amphibians with aquatic equipment, leads team dives, and holds scuba-diving certification courses for the Professional Association of Diving Instructors (PADI). Students will be taken from landlocked to fully submersible over the course of an online class and a series of pool and open-water certification dives. After completing the online component at their leisure, daring divers continue their trial by water with a three-hour pool session at the Bahia Mar Beach Resort & Yachting Center, where they will learn how to distinguish the legs of swimming tourists from saltwater anacondas. Experienced instructors will then join the cub divers to get their flippers wet in a series of four open-water ocean dives, which will be conducted over two trips.

Prospective divers must supply their own mask, snorkel, fins, logbooks, and weights, but are provided all other equipment, including a dive computer—though it can be revoked if you’re caught playing sea solitaire on it. At the culmination of training, graduates demonstrate their readiness to tackle the watery depths by triumphantly paying a $20 fee (not included in today's deal) to receive a PADI certification card.