Karlovy Vary or Zurich?

Neither town is for a beach trip, but Zurich at least lets you swim in the centre. Its clear lake has wooden bathing houses and lawned lidos, and at the Letten river baths swimmers drift down the Limmat with the current. You swim from grass and decks, roughly from June to early September.

Karlovy Vary has no open water in town at all. Swimming there means the warm spring-fed pools, or a trip of about half an hour to Lake Medard, a flooded former mine near Sokolov.

Zurich eats better and more widely. Alongside veal in cream sauce with rösti, fondue in guild-house dining rooms and an excellent chocolate tradition, the Kreis 4 and 5 districts have international and casual food and a solid fine-dining tier. The catch is that every meal is expensive.

Karlovy Vary sticks to hearty Czech cooking, such as roast pork, dumplings and svíčková with Pilsner-style beer. Its two treats are its own: warm spa wafers from the colonnade stalls and Becherovka, which is still distilled in town. Beyond the riverside cafés there are few kitchens with real ambition.

The two are broadly level, but they offer different things. In Karlovy Vary the attraction is the townscape itself: tiers of Belle Époque hotels in a narrow valley, listed by UNESCO among the Great Spa Towns of Europe, carved and columned colonnades, and the Vřídlo geyser erupting under cover. Its museums are small and specialised.

Zurich has the stronger collections. The Kunsthaus runs from Swiss painters to Monet and Munch, the Swiss National Museum covers the country's history, and the Rietberg shows art from Asia, Africa and the Americas. It also has Reformation history at the Grossmünster and Chagall's windows in the Fraumünster.

In Karlovy Vary an evening means a drink after dinner, not a night out. The spa crowd keeps early hours, so you choose between a hotel bar, a Czech pub or a flutter at the casino, and the valley is quiet well before midnight. The film festival in early summer is the one week when that changes. Parties and open-air bars take over the promenades, and for those few days the gap with Zurich narrows.

Zurich is where you go to dance. Electronic music is its real strength. At weekends, clubs in the old industrial districts keep going until daylight, the rougher bar strip of Langstrasse fills up late, and each August the Street Parade turns the lake shore into a huge techno party. On summer nights people drink beside the lake and the river. Even so, the cost of every round tends to end the evening sooner than the clubs do.

Karlovy Vary sits in green, rolling country. Beech and spruce forest rises straight from the spa quarter, and gentle graded paths lead to the Diana lookout. Further out are the moors of the Slavkov Forest, easy canoeing on the Ohře and skiing around Klínovec in the Ore Mountains.

Zurich's surroundings are on a much grander scale. The Glarus Alps rise at the end of the lake, the Uetliberg ridge starts a short train ride from the centre, and Rigi, Pilatus and ski areas such as Flumserberg are about an hour away for real mountain hiking or a winter day on the slopes.

Karlovy Vary's best outings are close and modest. Loket's river-bound castle is twenty minutes away, Mariánské Lázně and Františkovy Lázně are the other two spa towns of West Bohemia, and Bečov has its medieval reliquary. Plzeň and Cheb take longer on slow regional trains, and Prague is a long day by coach.

From Zurich, fast trains put much of Switzerland within easy reach. Lucerne is under an hour away, and Bern, Basel and St Gallen's abbey library take about an hour each. The Rhine Falls with Stein am Rhein, or a boat to Rapperswil, make easy outings, all without a car.

Zurich is much better set up for children. The zoo, with its Madagascar rainforest hall and elephant park, is a full day out, the lake lidos have shallow water and lawns, and the Technorama in Winterthur and Lucerne's Swiss Museum of Transport are short train rides away.

Karlovy Vary is safe and pleasant, but it is built for adults taking cures. Children enjoy the geyser, tasting spring water, the funicular and the wafers. After that and a trip to Loket castle, there is little else aimed at them.

Both centres are easy to walk, but Zurich's public transport is in another class. Trams, S-Bahn trains, funiculars and even the lake boats run on one integrated ticket, and the airport is a short train ride from the main station.

In Karlovy Vary you mostly walk the long strip of promenade beside the Teplá, using local buses and the funicular for the steep climbs to hotels. Regional trains are slow, so a car helps for the forests and villages.

Zurich offers more, at the very top end. Bahnhofstrasse runs from the station to the lake past watchmakers, jewellers and long-established department stores, while the Altstadt lanes and the viaduct arches in Zurich West add antiques and design shops.

Karlovy Vary's range is small, but what it sells is rooted in the place. You can buy Moser crystal from the maker's own showroom, local porcelain, Bohemian garnets, and spa cups to take home. Fur and fashion boutiques for spa guests fill out the promenades.

Karlovy Vary is by far the cheaper of the two. The grand hotels and colonnade restaurants charge for the setting, but Czech pubs and canteens a street away serve food and beer at local prices. Rooms cost most in summer and during the festival week.

In Zurich, everything is expensive, from simple hotel rooms and casual lunches to museum tickets and drinks. A visitor card, supermarket picnics by the lake and the free lidos help a little, but the gap remains wide.

Zurich's stages are of international standard. The Opernhaus offers a full season of opera and ballet, the Tonhalle Orchestra plays in its restored nineteenth-century hall, and the Schauspielhaus is a leading German-language theatre. Rote Fabrik and venues in Kreis 4 and 5 host jazz, indie and touring bands.

Karlovy Vary offers a gentler evening. Its symphony orchestra, descended from the old spa bands, plays light classics that sometimes move out onto the colonnades in summer. The Fellner and Helmer theatre hosts touring drama and operetta, and an autumn Dvořák festival adds a few highlights.

This is Karlovy Vary's great strength. The whole day is built around the drinking cure, sipped from a spouted porcelain cup at springs of different strengths, together with sanatorium stays that combine carbonated baths, peat wraps and medical consultations. For the full experience, book a spa stay, because public bathhouses are fewer than you might expect.

Zurich has some fine places to soak but no tradition to match. There are the thermal pools and rooftop pool in the vaults of the old Hürlimann brewery, winter saunas in the wooden lake baths with cold dips between sessions, and Baden's Roman hot springs twenty minutes away by train.