Margaret Thatcher's Greatest Moments

Margaret Thatcher, the former U.K. prime minister, died on Monday at the age of 87 after suffering a stroke. Known as the Iron Lady, Thatcher governed the U.K. from 1979 to 1990 and was the first woman elected to lead a major western state.

She will go down in history as the woman who transformed Britain's economy. Renowned for her political dominance in the 1980s, which saw a rolling back of the state and an emphasis on the free market. This broke the post-war pro-state consensus that dominated Britain for nearly three decades.

CNBC looks back at some of the greatest moments of her premiership.

By CNBC's Matt Clinch, with Kiran Moodley and Sebastian Martinez

Thatcher's first cabinet position was as Education Secretary under Edward (Ted) Heath's Conservative administration between 1970 and 1974. The abolition of free milk for elementary school children resulted in the school yard chant "Margaret Thatcher, Milk Snatcher."

Ted Heath had committed the ultimate Tory sin of losing three out of four national elections during his tenure. In 1975, Thatcher defeated Heath at the first ballot of a leadership contest and she became leader on Feb. 11.

Margaret Thatcher became the U.K.'s first female prime minister on May 4, 1979, with a tiny majority of 43 seats. In her opening speech outside Downing Street she famously quoted Saint Francis of Assisi: "Where there is discord, may we bring harmony. Where there is error, may we bring truth. Where there is doubt, may we bring faith. And where there is despair, may we bring hope."

For many, the Falklands War of 1982 was the defining moment of Thatcher's time as prime minister. While many opposed her decision to send troops to the distant Falklands islands, she was vindicated by a swift victory that saw her popularity soar and her majority increase at the 1983 election.

Baroness Thatcher lost two important political figures in her life to the IRA (Irish Republican Army): Airey Neave and Ian Gow. She herself narrowly missed being injured in the 1984 Brighton bombing that killed five people.

Undeterred, she still delivered her speech to the Conservative Party Conference the following day to much popular acclaim.

One of Thatcher's most controversial policies was closing the majority of Britain's coal mines, which led to the infamous miners' strikes between 1984 and 1985, and her confrontation with the miners' leader, Arthur Scargill. The result was a major victory for Thatcher, which massively weakened the grip of the unions within Britain.

Margaret Thatcher said of Mikhail Gorbachev, the last leader of the Soviet Union: "I like Mr. Gorbachev. We can do business together." On hearing of Thatcher's death, Gorbachev described her as a "great politician and an exceptional person" who helped end the Cold War.

Ronald Reagan was U.S. president for eight of Thatcher's 11 years in office and Thatcher was the first foreign leader to visit him after his inauguration in 1981. The pair soon found common ground with their anti-communist and free-market views and "Reaganomics" and "Thatcherism" became synonymous with the 1980s.

On news of Thatcher's death, U.S. President Barack Obama said: "Here in America, many of us will never forget her standing shoulder to shoulder with President Reagan, reminding the world that we are not simply carried along by the currents of history. ... We carry on the work to which she dedicated her life—free peoples standing together, determined to write our own destiny."

Thatcher's lowest political moment—before the party coup that ousted her from power—was a series of riots that spread across the U.K. in response to the Community Charge, a highly unpopular poll tax introduced to fund local government. The biggest demonstration took place in London, where violent confrontations between the police and protesters led to widespread looting.

The British electorate voted Thatcher into power three times, but it was her own party that finally ousted her from office. Following a poor showing in the first round of a leadership ballot, Thatcher stepped aside, and was eventually replaced by John Major, who served as prime minister from 1990 to 1997.

Almost 20 years after she left politics, Thatcher was honored with a statue in the Members' Lobby at the Houses of Parliament, which placed her alongside renowned British politicians such as Winston Churchill, David Lloyd-George, and Clement Attlee.

Thatcher's political reign was introduced to a younger generation in the 2011 film, "The Iron Lady," for which Meryl Streep's performance as the Iron Lady won her a Best Actress Oscar.