HAMBURG (Bloomberg) – Sex shops, adult cinemas, brothels and lap-dancing clubs jostle for clients alongside restaurants, dance clubs and live-music venues on the Reeperbahn in Hamburg, the city where The Beatles performed more than anywhere else.

John Lennon once said he grew up in Hamburg, not Liverpool. Paul McCartney described it as a "sexual awakening" for the teenagers from conservative 1950s England. "We were baptised in Hamburg because there were the girls," he says in his official biography. Most were strippers or hookers, he adds.

Hamburg's red-light district is also where The Beatles came of age as musicians. When they first arrived in 1960 to play gruelling six-hour sets at the Indra and Kaiserkeller clubs on Grosse Freiheit, they didn't know enough songs to fill the evening. By the end of 1962, they had played more than 800 hours in Hamburg, evolving from a hastily assembled band who only got their first assignment because three other groups declined, to a well-honed act on the threshold of enormous fame, with their first single, "Love Me Do," already in the UK charts.

It has taken almost 50 years for Hamburg to wake up to its legacy as the place where the world's most famous rock band cut its teeth. At long last, a museum called Beatlemania has opened on the Reeperbahn, near the newly named Beatlesplatz.

Beatlemania takes over five floors of what was once a museum of erotic art. For aficionados, the top floor is by far the most interesting, as it focuses on the group's Hamburg days, back when bassist Stuart Sutcliffe and drummer Pete Best were part of the band. Ringo Starr joined later.

There are paintings by Sutcliffe, messages of love on scraps of paper to his fiancee Astrid Kirchherr, postcards from Ringo to his grandmother and photos of the Beatles performing and relaxing after their marathon sets.

The band was first put up in two squalid, windowless rooms behind the screen of the Bambi cinema, a home they dubbed "the black hole of Calcutta." They washed in the men's cloakrooms and frequently were interrupted by early cinemagoers.

The St. Pauli area was then a rough district serving the sailors who landed at Germany's biggest port. Entertainment was the brothels and strip joints with unorthodox acts such as mud- wrestling women, the myriad dingy bars and the frequent street brawls. The Beatles first played at Indra, a shabby strip club.

In Hamburg, they were free from the constraints of home and cut rebellious figures – dressing in black leather, strutting and twisting on stage, taking Preludin pep pills to keep going. They were a far cry from the clean-cut, besuited boys groomed by Brian Epstein to serve as role models for teenagers.

They got into plenty of trouble, too. McCartney and Best spent a night in the Reeperbahn police cells after setting fire to a condom in their apartment. George Harrison was deported home for being underage in the bars and clubs. He was just 17.

At the museum opening, Horst Fascher, who brought The Beatles to the Star Club, reminisced about how his mother used to look after the boys, doing their washing and occasionally cooking them soup.

"It's good that this museum has come to St. Pauli," said Fascher, sporting a white beard and a walking stick. "It takes me back to the old days."

The initiative for a museum finally came from Folkert Koopmans, a concert producer who has invested 2.5 million euros ($3.53 million) in Beatlemania, which is purely a private venture. He is counting on 200,000 visitors a year.

A big yellow inflatable submarine protrudes from the front of Beatlemania. Downstairs is John & Paul's fish-and-chip shop. The lower floors cover well-trodden ground – stadiums packed with hysterical fans, the retreat to the studios on Abbey Road and the breakup. It's less interesting than the Hamburg section.

Even there, the show lacks comments from the Beatles themselves about their time in the city. While there are interviews with their Hamburg contemporaries on TV screens, more eyewitness accounts of the concerts and some recordings from the Hamburg days would be welcome. Still, it's good to have a museum at all, and improvements likely will come.

Hamburg's red-light district is slowly gentrifying. The sex industry is suffering from the advance of the Internet, which has curtailed demand for pornographic films and sex shops, and the advent of container ships, which has reduced the number of sailors in town. Restaurants and theatres are moving in, and the area is still a breeding ground for musical talent.

Beatles tourists should on no account miss the opportunity to do a guided walk with Stefanie Hempel, a 32-year-old singer/songwriter and Beatles fanatic who says she has about 100 biographies of the Fab Four at home.

With a ukulele shoved in her shoulder bag, Hempel takes tourists around all the clubs where the Beatles sang and hung out. You can pose in the doorway where Lennon stood for a photo that later became the cover of his "Rock 'n' Roll" album.

At the relevant spots, Hempel plays songs from the band's Hamburg days, such as "Twist and Shout," "I Saw Her Standing There" and "My Bonnie." She sings with so much enthusiasm and verve, it's impossible not to join in, tap your feet and twist a bit, even in broad daylight on the street.

Not to worry, this is the Reeperbahn, where anything goes.