To advertise the national dental services, "Folktandvården", decided to show the population what they really mean by "Nollhålsvisionen" (literal translation: the zero holes vision")
At night they taped up familiar holes all over Stockholm with nice flexible plexiglass. Holes in public garbage bins? Gone. Keyholes? Gone. Tunnel holes? Gone!
Most people are in on the stunt here, obviously because you can't just let bicyclist slam into tunnel walls doing their best Roadrunner impression, but it's realistic nonetheless.
Folktandvården handle around 75% of all children's dental needs in Stockholm, while the remaining percentage can afford to go to private dentists. Every third adult still goes to Folktandvården for dental care. Folktandvårdens goal is that children should have no cavities.