Gustavo Petro is sworn in as the first left-wing president of Colombia, before a crowd of hundreds of thousands at his inauguration in Bogota. The 62-year-old former guerrilla proposes plans for new peace agreements with the armed groups that finance drug trafficking and the end of the "war on drugs" that he considers a failure. "It's time for a new international convention that accepts that the war on drugs has utterly failed," says Petro during his inaugural address. IMAGES AND SOUNDBITES