You arrive in 'Zeebrugge' which is the port. But there are many tours and also the train to 'Bruge', Antwerp and other cities. We loved Bruge - especially the old town area. Lots of historic buildings and gorgeous old cathedrals. Nice, clean area to walk around in - don't try to park a car!
Lisbon is a big city and situated on 7 hills, so if you have trouble climbing then you should take a bus tour. We saw a medieval castle and cathedral. There are lots of shops and restaurants and the people are friendly and helpful. There are some wonderful views from the top of the hills and the bridge, which the ship went under, is the sister of the Golden Gate bridge in San Fran.
Go to the beach or visit the Everglades! Both are really worth doing. We saw so many alligators in Everglades National Park that it almost got to be boring. They have beautiful wild flamingos. Don't drive in Miami unless you like traffic!