"I trust that the majority have a will for change," says leftist candidate Gustavo Petro after casting his vote in Colombia's presidential election. Opinion polls show that many Colombians are pinning their hopes on Petro, an ex-guerrilla and former mayor of Bogota, to address poverty, rural violence, urban crime and endemic corruption in a country historically governed by the right. IMAGES AND SOUNDBITES TO COMPLETE 32BH7W8