It takes toughness to drill through more than 10,000 ft. of water and rock for oil, but Maria das Graças Silva Foster — the new CEO of Brazil's Petrobras and the first woman to run a major oil-and-gas company — is nothing if not tough. Foster, 58, spent her early childhood in a working-class favela on the outskirts of Rio de Janeiro and collected recyclable cans and paper to help pay for school. A chemical engineer by training, she joined Petrobras and stayed for more than 30 years. Her tireless work habits earned her the nickname Caveirao, slang for the armored cars Brazilian police use to clear out slums. Foster was helped to the top job by President Dilma Rousseff, a longtime friend — and, not coincidentally, a fellow female leader in a country known for its machismo. But with Petrobras spending $225 billion over the next decade to unlock oil off the Brazilian coast, Foster's experience — and her toughness — will be even more important than her political acumen.
Walsh is a senior editor at TIME