The world's biggest man-made lagoon, also referred to as the world's biggest swimming pool, is located at the San Alfonso del Mar Resort in Chile. It is a kilometer long, up to 35 meters deep and holds 250 million liters of water pumped in from the Pacific Ocean, which is only a short walk away.
Visitors can sail boats, snorkel and scuba dive in the ridiculously large pool, and the resort also features Jacuzzis "with ocean views," and "ocean aquariums" where you can dine with a different kind of "ocean view."
While many outlets have reported that it costs more than US$3 million to maintain, the actual cost is US$4,000 per hectare per month, including energy and labor, bringing the annual cost to US$384,000 -- which isn't anything to sneeze at.
The man-made lagoon is actually significantly more environmentally friendly than most others -- a new technology developed by a company called Crystal Lagoons uses up to 100 times less chemicals in comparison with traditional pool maintenance systems, and has a process of filtration with sound pulses that uses 2 percent of the energy that is traditionally used in filtration systems.