Older than Berlin and wrapped in the waters of the Havel, Brandenburg an der Havel is where the whole region got its name — and it turns its riverside old town into one big puzzle trail. This app-led scavenger hunt takes you through Brandenburg an der Havel on foot, using phone-based riddles to guide you from one landmark to the next. No guide, no fixed start time. • Cross to the Dominsel, the cathedral island where the city — and the...