Berlin impressions in 3 minutes.
berlin is the most populous city in germany not second
Who said it was second?
Berlin with a population of 3,748,148 in 2018 was the largest city in Germany and the 2nd-largest in the European Union after London/UK, which technically is out now.
More German cities: https://en.wikipedia.org/wiki/List_of_cities_in_Germany_by_population
Berlin docu, auf Deutsch, 1 hour 30 mins
How awful is life? Easy German Episode 256
Easy German asks people in Berlin.