The world's largest pool is located at the sea-side resort of San Alfonso del Mar in Chile. It was built in 2006 and is longer than 20 Olympic swimming pools combined. It is an astounding 115-feet deep and is filled with around 66 million gallons of water. The water is filtered from the Pacific Ocean, which the pool is very close to in proximity.
It was estimated to have cost $1.5 billion for the initial construction alone, and almost $4 million every year in upkeep costs.
The water is reported to be crystal clear; an attractive, shimmering turquoise where even the deepest depths highly visible during daytime. The temperature of the pool water is said to be 26°C after the sun has heated it - nine degrees warmer than the sea that it neighbours.
The pool is so large that boats are able (and allowed) to sail its water.