The tech behind smart cities

Turning contaminated river water into a swimming pool could soon be a reality for New York City's notoriously dirty Hudson River. And there's no chlorine necessary.

+POOL filters river water into the walls of the pool and purifies it with its layered filtration system.

+POOL tested its filtration system during five months this year in the Hudson River. A sensor recorded data about the pool's water, like the amount of rainfall, the depth and the temperature. This information was publicly available via a Google Drive dashboard.

In May 2017, +POOL hopes to have an Olympic-sized +POOL as a permanent fixture in either the Hudson or East River (with a walkway connecting it to mainland).

"We're hoping that it'll serve as a prototype for swimming in urban areas worldwide," said Archie Coates IV, a co-founder of +POOL.