“In 1931, Joseph Stalin’s Communist government blew up Moscow’s landmark Christ the Savior Cathedral in order to build what eventually became the mother of all Soviet public works projects: the Palace of Soviets, intended to be a combination conference hall/administrative building. But the project never came to fruition, so the Soviets designed and built a massive pool on the site instead.
“For years, it was the largest in the USSR. The Moskva pool, as it was known, was the size of two soccer fields and hosted thousands of Muscovites in search of a swim. Alas, it didn't survive the USSR: It was drained after the collapse of the Soviet Union and is now the site of a rebuilt cathedral.”
Data courtesy of interestingfacts.com