Bern is is the de facto capital of Switzerland.
On December 31, 1999, Tony Stark was invited to Bern in order to give a lecture on integrated circuits as the head speaker. Stark was able to give his lecture despite being heavily drunk, later defined as being both edifying and unintelligible, depending on the asked person.
Having finished the lectures, Stark assisted to ensuing party where he flirted with Maya Hansen while his bodyguard Happy Hogan tried to keep people from approaching Stark. Ho Yinsen greeted Stark before leaving, and introduced him to Doctor Wu, a Chinese cardiologist and their guest in Bern, mocking both of them due to his drunkenness.
Stark and Hansen were approached by Aldrich Killian, founder of a privately-funded think tank called Advanced Idea Mechanics or A.I.M. and great admirer of their work. Killian sneaked into their elevator and revealed that he was very interested in Hansen's work, offering to recruit her into A.I.M.
To get away of Killian, Stark lied to him and told him to wait on the roof of the building, and he would join up after taking a quick drink. Killian believed him and waited for him at the roof until the celebrations for the New Year started, realizing Stark was not going to come. He considered suicide, but thinking that none knew he was even there made him realize that anonymity was the rule he would follow to achieve his goals.
Stark reviewed Hansen's Extremis project, that intended to access the area of the brain responsible of repairs and healing in order to chemically recode it. Happy Hogan touched one of the plants serving as test subjects for Extremis, and breaking one of its branches activated the Extremis-induced regeneration. Stark and Hansen entered the bedroom and while Hansen explained possible applications for Extremis, such as disease prevention or even limb regrowth, Stark continued flirting with her.
The plant exploded, as it was one of the possible side effects for the use of Extremis, and Hogan rushed to protect his boss, putting in an embarrassing position. At that moment, the guests gathered in the building started shouting to celebrate the New Year that arrived.
The following morning, Stark left Hansen without saying goodbye, just leaving her a note while she was working.