At what point does a swimming pool become a swimming… lake? Sea? Ocean?

largest pool in the world

The swimming pool at the San Alfonso del Mar Resort in Algarrobo, halfway up the coast of Chile, is recognized by Guinness World Records as the largest pool in the world.

With a deep end of 115 feet — deeper than the LENGTH of most swimming pools — the pool measures 3,324 feet long and covers an area of nearly 20 acres, or more than 860,000 square feet. To give you a sense of its massive scale, an official Olympic-sized swimming pool measures 164 feet long, 6 feet 7 inches deep, and holds 660,000 gallons of water. The Alfonso del Mar pool’s capacity? 66 MILLION gallons. That’s the capacity of one hundred Olympic-sized swimming pools combined.

The pool took nearly 5 years to build, is estimated to have cost somewhere between 1.5 and 2 billion dollars, and runs 4 million dollars per year in maintenance costs. To be fair, that does buy you a whole lot of pool. Guests at the resort can spend a day at the pool kayaking, scuba diving, or relaxing in a full-sized sailboat.

The pool is fed by a massive suction and filtration system that supplies saltwater from the adjacent Pacific Ocean. It relies strictly on the sun for heating, which manages to raise the water’s temperature to 79 degrees Fahrenheit, about 16 degrees above the local coastal ocean temperature. If that isn’t toasty enough to suit your tastes, you can pay an additional fee to visit the glass enclosed pyramid situated within the pool that features warmer water, a heated beach (yes, the sand itself is heated), and an attached gym.

If you’re okay with settling for something a little more modest than the world’s largest pool, the largest residential pool in the United States is located in El Campo, Texas. Measuring 50,000 square feet, it features a 21 foot water slide, six waterfalls, a bar, and a 500 foot long ‘lazy river.’ It is rather tiny in comparison to the del Mar pool, holding a mere 750,000 gallons of water.