Bern 2000 was technical conference held in Bern, Switzerland. It gathered hundreds of people of various origins, affiliations and occupations, including the genius billionaire Tony Stark, the scientist Maya Hansen, the founder of A.I.M. Aldrich Killian and the surgeon Ho Yinsen. During the conference, Stark gave a lecture about integrated circuits all the while being heavily drunk.
During the conference, Stark met with other attendants like Ho Yinsen and Wu, but he most importantly met and flirted with Hansen. The two partied together after the lectures, waiting for New Year to come, and Stark suggested to Hansen to go to her hotel room so they could review her work. Once in the elevator, and despite Happy Hogan trying to interfere, they were approached by Killian, who wanted to associate with Hansen. As they had reached their floor, Stark told Killian to wait for him on the roof to discuss a potential collaboration.
However, Stark never made it to the roof to meet Killian. Instead, he remained in Hansen's room to discuss their work and the two spent the night together, leaving Killian alone on the roof to watch the fireworks fired for New Year. The humiliation he received from Stark during Bern 2000 deeply affected Killian, who grew a desire to exact revenge on Stark, which would result in a war in the years to come.
Years later, when both Hinsen and Stark were held captives by the Ten Rings, Hinsen reminded Stark that they had met during Bern 2000, although Stark claim he did not remember it, which Hinsen perfectly understood since Stark was heavily drunk at the time.