Anders Houmøller Thomsen: "One startling anecdote goes: 'We played in Copenhagen back in 1991 at some youth center. People actually had sex on stage while we played', explained the 37-year-old singer."

Nikolaj Heltoft: "The list of now-superstars who have played in Ungdomshuset is very long. They came there before anybody else in Copenhagen knew who Bjork and Nick Cave were and in 1991 an American teenage punk band called Green Day played in the Ungdomshuset before shooting off to world fame."

"After the first week, when they discovered that it's a Danish tradition for punks to throw beer at bands they like, their instruments were toast. Luckily - for him - Armstrong had brought Lawrence Livermore's amp instead of his own. Replacing the instruments was out of the question, as they were barely earning enough money to keep everyone fed and traveling from show to show. The band ended up borrowing new equipment every night. 'Seriously,' says Tre Cool, 'I was using guys' kits where the drummer would say, 'If you screw up my kit, I'm gonna stab you.''"

"Green Day has played several times in Denmark, including Roskilde Festival in 2005, The Forum in 2009 and Skive Festival in 2010. But it was an experience in 1991 that remained on the retina when Green Day had to share the stage with a loving couple. What is your best memory from your many concerts in Copenhagen? Is there anything that sticks back then, there were a couple who had sex on stage?
Billie: Oh my god!
Mike: We played in the Youth in Christiania, and there was some fucking crazy stuff there.
Billie: It was a 10-year anniversary, and we played at "punk night" and it was a crazy party. While we played, people started throwing beer, and I only had one guitar, so I had to play like this (showing how he protected the guitar). All of a sudden there were a few left that just went down. They were quite full and did so complacent on stage as they possibly could.
Mike: It was like Altamont (Free Speedway Festival), haha!
Billie: They both had military boots on."