Colombia returned to the polls Sunday to choose a successor to President Alvaro Uribe. The second-round balloting pitted a former defense minister, Juan Manuel Santos, 58, against his rival Antanas Mockus, a former Bogota mayor running on a Green Party ticket. Santos, the big winner in the first round of voting on May 30 with 46.6 percent against 21.5 percent for Mockus, has promised "to keep in place the legacy of Uribe, the best president Colombia has had."Duration: 01:05