The Danish Air raid sirenes allways gives me the creeps, I think it's the clear sound that gets me. Unlike other sirenes that has a harsha tone, the Danish ones have a almost sterile tone, convaying the feeling of "this sound is vary important, stop now and go Inside. Like a scary Teacher"

Starts at 0:15 and later has a "all clear" tone later on on youtubes

Then again it might just be because I had to listen to it as a kid, and I was a weird ass kid