Berlin or Heidelberg?

Neither has a coast, but Berlin makes a proper summer pastime of lake bathing. The sandy lido at Wannsee, the Müggelsee and forest lakes such as Schlachtensee are all reachable by public transport, and they are warm enough to swim in July and August.

Heidelberg offers much less. The Neckar is not for swimming, so on hot days you choose between the town's outdoor pools and gravel-pit lakes on the Rhine plain, about half an hour away.

Berlin eats more widely. Its strength is variety rather than local cooking: döner and Turkish bakeries, good Vietnamese and Levantine food, street-food nights in the market halls and a serious fine-dining scene, all of it casual.

Heidelberg's appeal is regional and narrower: Maultaschen, Flammkuchen, spring asparagus and above all wine from the Bergstrasse and the Palatinate. Around the castle many places cater to day-trippers, so the better meals are in the side streets, in Neuenheim and in the wine villages nearby.

Berlin is in another league for sightseeing. Museum Island's five museums, the old masters of the Gemäldegalerie and Charlottenburg Palace would be enough for a trip on their own, and on top of that the Reichstag, the Holocaust memorial and Bernauer Strasse tell Germany's twentieth century where it happened. What it lacks is a pretty, intact old town.

Heidelberg has exactly that: a Romantic castle ruin above a well-preserved baroque Altstadt, the Old Bridge and Germany's oldest university with its graffiti-covered Student Prison. It is beautiful and easy to take in, but a day or two covers it.

Berlin is one of the world's great club cities. Techno nights in old power stations and warehouses run from Saturday into Monday behind strict doors, and away from the clubs there are smoky Kneipen in Neukölln, cocktail bars in Mitte and canal-side beers in summer.

Heidelberg's nights belong to its students. The Untere Strasse fills with small bars in term time, and the old student taverns have real character. On weeknights and out of term the town goes to bed early, and anyone after a big club night takes the train to Mannheim or Frankfurt.

Heidelberg has the countryside right on its doorstep. The Odenwald forest starts at the edge of the old town, the Philosophers' Walk and the Königstuhl funicular lead to hours of woodland trails, and the Neckar valley and Bergstrasse vineyards are good for cycling and walking.

Berlin's outdoors is flat and needs more effort: the Tiergarten, the Tempelhof runways, the Grunewald and the Havel lakes for sailing, plus the Wall Trail for an easy ride. It is green and pleasant, but there are no hills to climb.

Heidelberg sits among a dense cluster of excursions. Speyer's Romanesque cathedral and the palace gardens at Schwetzingen are half an hour away, while Worms, Lorsch, Maulbronn, the castle villages up the Neckar and the Palatinate wine villages fill several more days. Strasbourg is possible at a push.

Berlin has Potsdam, whose Sanssouci palaces are as good a day out as any in Germany, plus Wittenberg, Leipzig and the Spreewald. Dresden makes for a long day, and after that the choices thin out quickly across the flat Brandenburg countryside.

Berlin gives children more to do. Two large zoos, a dinosaur skeleton at the Natural History Museum and the hands-on trains and planes of the Museum of Technology can fill several days. The flat streets make pushchairs easy and the trains manage them well, though some of the historic sights are too heavy for young children.

Heidelberg is smaller and calmer. Its highlights are the funicular, a little fairy-tale park on the Königstuhl and river boat trips, and the Speyer technology museum and a theme park are within easy reach. The cobbled, sloping Altstadt is hard work with a pushchair.

Berlin's U-Bahn, S-Bahn and trams link a large city quickly and run all night at weekends. The flat streets and bike lanes make cycling easy. You will still ride a lot, because Mitte, Kreuzberg and Charlottenburg are separate centres.

Heidelberg is the opposite problem in miniature. The Altstadt is one long walkable strip, but the station is a tram ride away and the castle approach is steep. The regional fare system makes the surrounding towns easy to reach without a car.

Berlin is the better shopping city, mostly for independent and second-hand finds. Concept stores around Hackescher Markt, vinyl and vintage shops in Kreuzberg and the Sunday flea markets at Mauerpark and Boxhagener Platz are the highlights, with KaDeWe and the Kurfürstendamm for brands.

Heidelberg's shopping is essentially one long street, the Hauptstrasse, with chains at one end and steins, cuckoo clocks and Studentenkuss chocolates at the other. A bottle of Bergstrasse wine is the best thing to take home.

The two cost much the same, with Berlin a little easier on the wallet. Its hotels are good value for a capital, and döner, Vietnamese canteens and Kneipe beer keep daily costs down, though museums and fine dining soon add up.

In Heidelberg the strain is beds: the town has few rooms for the number of visitors, so many people stay in Mannheim and come in by train. Meals in student cafés and taverns stay cheap, and the castle's entry fee is modest.

Berlin has a schedule few cities match: three opera houses, the Berlin Philharmonic in Scharoun's Philharmonie, the Konzerthaus and famous theatre companies such as the Berliner Ensemble. Visitors who don't speak German can stick to opera, dance and the Friedrichstadt-Palast revue, or go to the jazz cellars.

Heidelberg does well for its size. One municipal theatre covers opera, drama and dance, the Heidelberger Frühling brings chamber music in spring, and summer shows are staged in the castle courtyard. For anything bigger, Mannheim's house is twenty minutes away.

Berlin's wellness is German sauna culture inside the city: large clothes-free sauna complexes with infusion rituals, and the columned halls of the Stadtbad Neukölln. Lazy Sundays in café gardens complete the picture.

Heidelberg has little in town beyond hotel spas, but it is quieter by nature. Evenings on the Neckar meadows and forest paths above the Philosophers' Walk calm you down, and the Kraichgau thermal baths and Baden-Baden are close for real spring water.