Margaret Thatcher, Britain's first female prime minister, held the office for more than 11 years, including during the entire 1980s. In that time, she left a major mark on U.S. politics, mainly through her close relationship with President Ronald Reagan.
Here's a look back at the five moments that stand out:
1. "The second most important man in my life": Bound by opposition to communism, Thatcher and Reagan shared a close bond throughout the 1980s. Together, they provided a united Western counterbalance against the Soviet Union. Thatcher once called Reagan the "second most important man" in her life.