Hello - I'm planning to be in Utrecht, Netherlands from August 28 - Sept 9, when my daughter starts her semester abroad at the university. I'm looking to do some day trips and would like to dip down in Belgium. Travel by train or bus. We've both been to Brussels already. Of course we want to go to all three of these cities, but if we only can visit one, which is the best one-day experience? Mostly we like to walk around and look at the architecture, sit in a café and just soak up the atmosphere, maybe buy a souvenir, and maybe drop into a museum.
How would you rank these three cities? Am I missing something else significant? Merci.