By some miracle of fate, Rob & I visited Gdansk, Poland during St. Dominic's Fair. A tradition that stretches all the way back to 1260 AD, when Pope Alexander IV granted the Dominican monks the right to
party in the streets hold a fair.
The streets are packed with venders (many selling amber harvested from the Baltic Sea), travelers & a bevy of street performers. It is a really jolly time to visit, but you if you are not into crowds, then I would skip Gdansk during the St. Dominic's Fair. The amount of people on the streets combined with the heat of the Summer (the Fair is held in late July until early August) can be a bit overwhelming.
Fortunately, Saint Mary's Church is located right in the thick of the madness & here you can find solace from the crush of people & the heat. A good thing to note: almost all Churches in Poland are free to the public.
On the outskirts of town, you can still see ruins caused by bombing during World War II. Some may see the crumbling buildings as an eye-sore, but to me the ruins are a powerful memorial - a reminder that the war was not that long ago.