The system driving this operation is called district cooling, and its technology long predates this summer’s Olympics. The first system of its kind was built in 1962 in Hartford, Connecticut, and has since grown to be one of the largest in the world. The city’s gas company at the time had connected to all the interstate pipelines, bringing a surplus of gas to the city, which went unused in the summer. So a district energy system was created through which gas could be used to chill water and cool buildings in the summer, and steam for heat in the winter.

Created in 1991, Paris’ district cooling network is already Europe’s largest, currently serving more than 2,000 buildings in the south of the city