In Nordic countries, there’s a norm of letting babies take a nap alone outside in their pushchairs. Wander down a street in Denmark, Sweden, Norway, or Finland and there’s a chance you’ll see strollers and prams quietly sitting by themselves with a sleeping baby inside, even on a chilly winter day. It’s perfectly acceptable for parents to slip into a cafe for a coffee and leave their baby outside with no qualms. In fact, it’s not unusual to see a mini car park of pushchairs lined up outside buildings. The practice may seem strange to foreign eyes, but it’s a widely accepted tradition among Nordic parents and even encouraged by midwives. All in all, the practice of letting babies nap outside is perceived to boost kids' health and serves as a way to express age-old cultural traditions.

Source: IFL Science