Day of the city. It's very nice, there are lots of people to speak with. Of course, it's a memory of your city.
Also there can be much competitions, presents, parties.
It's a nice idea to spend time with friends. You might see lots of beautiful buildings, people.
Of course it's a holiday for people you can have a rest, relax at home with parents.
This day is only yours, and you can spend it like you want.