This enormous pool can be found at the San Alfonso del Mar resort in Algarrobo, Chile. It holds 66 million gallons of water and is 20 times longer than an Olympic-sized swimming pool! Completed in December of 2006, this saltwater lagoon took 5 years and over $1.6 billion to be built! It has been officially recognized by the Guinness World Records as the World's Largest Pool which measures 3,324 ft. long.
It uses a computerized filtration system to circulate water from the Pacific Ocean through the pool and then back out again. Despite the fact that the water is heated by sunlight alone, maintaining this insanely large pool still costs around $3.2 million annually!