I've stood outside Hansa Studios wishing I could go in! Apparently the only way you can go inside (unless you work there, of course ) is if you book in advance to go on one of the U2, Bowie or Depeche Mode guided walking tours around their old haunts, that an independent Berlin company does. A visit inside the studios is included with the walking tour but if I remember it's pretty expensive. I'm sure it's well worth doing though, if you can afford it. They only do the tours at certain times of the year, if I remember correctly.