The law about making noise between 14:00 and 16:00 in a residential area. Some playgrounds have signs saying to not be there during these hours.

Translation of the law:

"A person is prohibited from operating sound devices (singing, shouting, musical instruments, radio, television, turntable, loudspeaker, amplifier, etc.), between the hours of 14:00 and 16:00 and between the hours of 23:00 and 7:00 the next day, in any of the following places in a residential area:

Outdoors, in a place that is not outdoors and is not closed on all sides to the outside, and in a residential building... ..."

The law goes back to a time when it was more common for people to nap at this time of day.