One key event was her appointment as the first female U.S. Secretary of State in 1997. This was a huge milestone for women in politics. Another important part of her life was her involvement in NATO's expansion.
A key event was her growing up during World War II, which no doubt influenced her views on international relations. Her academic achievements and rise through the political ranks were also important. As Secretary of State, her participation in various international summits and meetings was a regular feature. For instance, she was part of discussions on global economic issues and climate change - related diplomatic efforts in the international community.