A few versions exist to describe what is celebrated on Sweden’s national day (June 6th), but at the end of the day Swedes don’t seem to care much about it anyway. For the non-initiated, there’s a wiki page available to tell the story.
It’s basically a day when all the yellow & blue flags in Sweden are on display and everyone is out and about in the city, enjoying their day off (since it’s a bank holiday) and mostly shopping.
We started our nice day trip on Kungsholmen, walked by Gamla Stan and Stockholm Slott, continued towards Kungsträdgården and finished the day with a stroll through a green patch in Älvsjö. We even had some sun throughout the day, which made it even better.