One of the nicer ways to welcome the shorter days in Berlin is the Festival of Lights. It is an open-air light gallery with video art projections on many of the city’s top landmarks. This year’s motto is “Together We Shine” and will display in 86 different locations throughout the city. If you head to the TV Tower, you can do a nice walk then through the Nikolai Viertel and over to the Museum Island to catch some of the central sites. You can see the schedule and further details about the program and all the other locations here: https://festival-of-lights.de/en/das-festival/programm/
It started on September 11th and goes until the 20th from 8pm to midnight, so probably best to bring the kids on the weekend!
NOTE: If too many people gather at a particular spot and are not maintaining social distancing they will need to shut down the illuminations.