Strumming in the Subway.(subway musicians popular in Europe's big cities)

Looking to hear some nice, free music this summer? You could do a lot worse than to head underground. In the subway stations of Europe's biggest cities, busking is surprisingly popular, not just among tourists but among locals and city officials as well. Sometimes the music is even good.

That's because the competition has really heated up. Once the province of every amateur accordion player and karaoke crooner, busking in many places now requires a permit. In Paris, where there are 360 licensed subway musicians, only one in three makes the cut. Rotterdam started giving out busking licenses in 2000. And just last month London, where illegal buskers have long waged a guerrilla war with police, acceded to the demands of the public (eight in 10 say they want music in the Tube) and made the practice legal. Over the next four months, auditions will create a pool of some 300 musicians who will rotate through the Underground.

Besides looking for good musicians, judges are looking for diversity. From Bond Street to St-Michel you'll hear Gypsy folk songs, Irish reels, blues guitar, acoustic folk-rock, accordion jigs, African drumming, Latin rhythms and, of course, the standard Bob Marley and Beatles covers. Indeed, certain stations are renowned for certain sounds. London's Oxford Circus has long been known for its blues, while classical-music fans can enjoy a (nearly) free concert at highbrow South Kensington. In Paris the popular African drumming group Christ can often be found at the Republique station; at the Opera station, predictably, classical tunes are more common. Now French busking fans can even ...