Cologne or Frankfurt?

Neither city is a swimming destination, but Cologne gives you a little more choice on a hot day. Several flooded gravel pits on its edge, Fühlinger See, Escher See and Otto-Maigler-See, have grassy banks and small sandy stretches.

Frankfurt has outdoor pools and the Langener Waldsee in the southern forest, which has sandy shores and warm water in high summer. In both cities the river is for sitting beside, not swimming in, and the sea is out of reach.

The two eat in a very similar way, and neither is a reason to travel on its own. The difference is the drink at the centre of the meal. In Cologne it is the Brauhaus, where Köbes keep replacing small glasses of Kölsch until a beer mat stops them, served with black pudding and apple or the Halve Hahn cheese roll.

Frankfurt's version is the apple-wine tavern in Sachsenhausen, with tart Apfelwein from stoneware jugs, Grüne Soße and Handkäs mit Musik at shared tables. Frankfurt also has the better single food stop in the Kleinmarkthalle and cheap global eating in the Bahnhofsviertel. Cologne's best everyday alternative is the Turkish and Middle Eastern cooking along Venloer Strasse.

Cologne has the stronger sights. The cathedral, with the Shrine of the Three Kings and its stained glass, comes first, and behind it is a layer Frankfurt cannot match: twelve Romanesque churches and Roman remains from two thousand years of history. Museum Ludwig's Pop Art and the Wallraf-Richartz make its museums strong too.

Frankfurt's case rests more narrowly on the Museumsufer, where the Städel stands out, and on a compact rebuilt core around the Römer, the Paulskirche and Goethe's birthplace. Both cities were largely rebuilt after the war, so neither has an intact old town, but Frankfurt adds a skyline of towers unlike anything else in Germany.

Cologne is the better night out by some way. Evenings move from the Altstadt brewhouses to the Belgian Quarter's bars, the Zülpicher Strasse student strip and Ehrenfeld's clubs in old factories, and the gay scene around Rudolfplatz is one of Germany's largest. At Carnival the whole city becomes a street party for days.

Frankfurt goes out mostly on Friday and Saturday, in the Bahnhofsviertel's cocktail bars, the cider taverns and pubs of Alt-Sachsenhausen and the neighbourhood bars of Berger Straße. What sets it apart is a small, serious techno and house scene, rooted in the electronic music history it shares with Offenbach.

Both offer gentle, green country for walking and cycling rather than anything dramatic, and both have long flat riverside cycle paths and a large Stadtwald. Frankfurt's hills start closer: the Taunus and the 880m Großer Feldberg rise just beyond the northern suburbs.

Cologne takes a little longer to reach higher ground, but the choice is more varied once you do. There is the volcanic Siebengebirge with the Drachenfels crag, the reservoirs of the Bergisches Land, and the Eifel national park with its crater lakes about an hour away.

Both are excellent bases, but Frankfurt reaches further. Heidelberg and the Rhine Gorge are each about an hour away and Würzburg's Residenz a little more. Closer in are Mainz, Wiesbaden, Darmstadt, the Rheingau vineyards and the imperial cathedrals of Speyer and Worms, and Cologne itself is an easy day out.

Cologne's list is shorter but still strong. Brühl's palaces, Bonn, Düsseldorf and Aachen are all within forty minutes. Its own advantage is crossing the border, to Maastricht, Liège and Brussels, which is something Frankfurt does not offer.

Cologne is the easier choice with children. The zoo with its elephant park, the Chocolate Museum's production line and the cable car over the Rhine can fill several days, and Phantasialand, one of Europe's major theme parks, is a short trip away at Brühl. The one time to avoid is Carnival.

Frankfurt works well for a few days. It has the Senckenberg's dinosaur hall, a central zoo, the Palmengarten and boat trips past the skyline, plus a wildlife park and a small fairy-tale park in the Taunus. What it lacks is a single attraction worth the journey on its own, the role Phantasialand plays for Cologne.

Both are easy without a car, with walkable centres. Cologne's advantage is how you arrive: the main station stands right beside the cathedral, and the Altstadt, the museums and the river are a short flat walk away, with the Hohenzollern Bridge leading across to Deutz.

Frankfurt's strength is its connections. The airport is about a quarter of an hour from the centre by train, and one integrated network covers both the city and the region, including the Taunus, Wiesbaden and Mainz. On the downside, Cologne's trams can be crowded and irregular, and Frankfurt's lines and zones take time to learn.

On the high street they are almost interchangeable: Cologne has Schildergasse and Hohe Strasse, and Frankfurt has the Zeil with its malls. The differences are in the smaller streets.

Cologne has a real local speciality in Eau de Cologne from the historic perfume houses on Glockengasse, independent shops in Ehrenstrasse and the Belgian Quarter, and its Christmas markets in Advent. Frankfurt has more luxury around Goethestraße, boutiques on Berger Straße and Schweizer Straße, and a Saturday flea market on the Main bank.

Cologne is easier on the wallet, mainly because its hotels are priced for ordinary visitors rather than business travellers, and the cathedral and many churches are free to enter. Rooms get expensive there mainly during trade fairs and Carnival.

Frankfurt's hotels are aimed at business travel and become scarce in fair weeks, though weekends and summer bring prices down. Eating is good value in both, at the brewhouses in one and the cider taverns and Turkish grills in the other, and in Frankfurt the Museumsufer pass helps keep sightseeing costs down.

Both have a full stage life, with different strengths. Cologne's lies in its orchestras: the Philharmonie beside the cathedral is home to the Gürzenich and WDR orchestras, and the broadcaster adds a big band and choirs. On the popular side there is electronic and experimental music, gigs in Ehrenfeld and the Südstadt, and the dialect bands of the Carnival sessions.

Frankfurt leads with its opera company, known for adventurous productions. Around it are concerts at the Alte Oper, contemporary dance at Mousonturm, an English-language theatre and cellar jazz clubs. Its stages are quieter in summer.

The real difference is where you go to unwind. Cologne keeps it within the city: German sauna landscapes, and a thermal bath in the Rheinpark that looks across the river to the cathedral. Aachen's hot springs are under forty minutes away.

Frankfurt has little of its own beyond pools and hotel spas, but spa towns surround it: Bad Homburg's thermal baths, Wiesbaden's Art Nouveau Kaiser-Friedrich-Therme, Bad Nauheim and Bad Soden. Cologne's busy centre and Carnival make it the less restful of the two at times.