In Finland we have had a few markets that have tried to stay open for 24hrs, but without a success. And when I returned back to Finland and was used to go shopping food in the middle of the night, couldn't I continue this habit anymore. Sleepless hungry nights.
Then they did it: a 24 hrs open Alepa in Mannerheimintie. It was perfect for me, because I was working near by that Alepa and sometimes I was so busy because of my work, that I didn't manage to go to market during the daytime, so I did my shoppings in the night.
Also there are some gas stations serving 24/7, but this Alepa is brilliant!