Musicians, singers and other performers joined in during the quarterly test of Sweden's emergency notification system this week.
At 3 p.m. Monday Sweden's warning sirens sounded in their routine test.
But this time, the wailing horns were accompanied by sounds from musicians, singers, rappers and poets across the country.
The initiative was created by a group of artists who want to reduce the sense of public fear or angst in Sweden.
Viktor Brobacke was one participant who played his trombone during the 2-minute long test.
There are more than 4,600 sirens in Sweden that are used to alert residents to natural disaters or public emergencies.