Booked Europe trip from USA, first stop Berlin, to Amsterdam, to Brussels, to Paris and back. Couple of questions:

1. All family members with US Passports, do we need visa for any of these countries?
2. We only planned for Berlin in Germany, but thinking of adding Munich too..What do you guys think of Munich, or any other German city in place of it?

Apart from standard tourist attractions in Berlin, anything else you guys recommend that is must?

Thanks in advance.