She was a giant on the political stage and Britain's first female prime minister. Margaret Thatcher has died at the age of 87 after suffering a stroke. Dubbed the Iron Lady, Thatcher transformed Britain -- breaking unions and privatizing state industries. The daughter of a grocer, she rose to the top of Britain's snobbish hierarchy the hard way and envisioned a classless society that rewarded hard work and determination. Tributes to Thatcher are pourning in from across Canada, including Prime Minister Stephen Harper. He is remembering Thatcher as a giant among leaders who defined contemporary conservatism. Harper credits Thatcher, along with Ronald Reagan and Pope John Paul II, as having played a key role in ending the Cold War. Harper says her leadership was an example to the world and she deserved to be called the "Iron Lady".