Lauren Laverne presents a countdown of some of the most memorable moments from the decade, a period shaped by the rise of reality TV and social media. World-changing events in the headlines included the election of Barack Obama, the 9/11 terrorist attacks and the introduction of the Civil Partnership Act to the UK. Gnarls Barkley made musical history when Crazy went to number one on downloads alone, while the England cricket team regained the Ashes for the first time in 18 years.