BERLIN

While not a complete guide, here are a few ideas to get you started:

Visit to the Botanical Gardens + coffee and cake at the Garden Academy (Garden Akademie) —> this is in Steglitz which is a bit more out of the center but worth it on a sunny day :)

Walk around in the evening and bring a picnic dinner at the Tempelhofer Feld (the old airport for the Germans and US Army base) —> there might be an interesting tour here if your fam is interested but I didn’t do one since I was only there in the evening (probably also another good thing to do on a sunnier, non-windy evening)
Walk around Mitte (a very cool, hip up and coming neighborhood with nice shops and cafés), here you can walk through the Hackeschen Höfe (or small courtyards with different special goods, like shoes and a tile job that you should visit with art nouveau style
East Side Gallery for a closer look at the wall, recommend a guided tour for more history and information on the murals

Maybackufer flea market —> this is near Mitte so could be good to combine with that morning, here there are a lot of random people that just set up a stand and sell their old things, there are also food stands and coffee and good vibes (the pro flea market shoppers wear black tights so they can quickly try anything on, I learned)

Exploring around the Charlottenburg neighborhood, this area is super lovely and has nice restaurants and a bakery called Zeit für Brot (which is known for its circular buns, kind of like a cinnamon bun but different)
Sometimes cool exhibitions at the Amerika Haus for a rainy day
Neuköllen is also a cool new up and coming neighborhood which is near the East Side Gallery to explore