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Someone put up a tent on their balcony to escape their heat-trapping apartment during the night.
(discuss.tchncs.de)
Third extended heat wave within 6 weeks.
The previous one exceeded 40°C, and the buildings not yet had time to completely cool down from that one before the third wave hit.
I was considering putting up a tent in my garden myself, but as I own a ground floor flat, the indoor temperatures did, with the help of some additional cooling measures, thankfully not exceeded 27°C.
Beat me to it, a lot of the apartments around here built prior to AC had these, but many have since been removed or enclosed into conditioned living space. All you'd need is a bug net on a balcony to recreate it, unless you sleep in the buff.