Ambulance and police cars outside an Islamic center in central Zurich on Monday after three people were injured by gunfire. Police say the gunman later killed himself. Michael Buholzer/AFP/Getty Images hide caption

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Michael Buholzer/AFP/Getty Images

Photos of Luanda, Angola, tell a tale of two cities: sprawling poor neighborhoods and a glitzy waterfront. Saul Loeb/Getty Images; Michael Gottschalk/Getty Images hide caption

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Saul Loeb/Getty Images; Michael Gottschalk/Getty Images