Good afternoon, kedves Budapestiek!

I'm writing because I'll be coming to Budapest (for the first time) in a short while, also being in the city for the August 20th Celebrations.

I was curious what other events/sights are "must-see" on the National Day of Hungary, excepting the morning Parade/airshow, and the firework show in the evening (where I'll 100% be there)?

Did I understand correctly that all museums will be free on the 20th of August? Will there be any other cost-free activities on that day? (I have to admit that I'm on a tighter budget :) )

Also, do they usually sell special souvenirs on the occasion of the National Day? I'm half hungarian, so I'd also want to honour my heritage.

Thanks for your answers!