Every Berlin walk should start on the island in the river, because that is where the city decided to keep its treasures. Museumsinsel is five museums, a cathedral, and a rebuilt palace on a spit of land in the Spree — three kilometres that carry you from Prussian ambition to GDR concrete in under an hour and a half.
Come in from Hackescher Markt and meet the island at the Bode-Museum's sharp prow, where the dome sits right on the water. Walk south past the Pergamonmuseum — shut for refurbishment until at least 2027, so admire the colonnade and move on — to the Lustgarten, where Schinkel's Altes Museum spreads its columns behind the lawn. The Berliner Dom is next, heavier than it needs to be; climb the dome walkway if the legs allow.
Then across to the Humboldt Forum, the royal palace rebuilt three-quarters of the way, and into the Nikolaiviertel, a medieval quarter the GDR reconstructed in 1987. End under the Fernsehturm at Alexanderplatz, where every line in Berlin seems to meet.
