3. Margaret Thatcher (1925-2013)
Nicknamed the “Iron Lady”, Margaret Thatcher was the first female prime minister of the United Kingdom and she held the office longer than any other prime minister of the 20th century.
A popular leader, she stood up to powerful labor union officials and worked to promote free trade. She took office during an economic recession and she implemented strategies to get people back to work. Her “Thatcherism” programs were successful while controversial.