Colombians will choose among a leftist promising change, a center-right candidate seen as the natural successor to the incumbent leader, and an eccentric business magnate in a presidential vote on Sunday.
Gustavo Petro, the leftist, has consistently led opinion polls, with around 40% of voting intentions. If no one secures more than 50% a run-off will take place on June 19, which surveys suggest Petro would win.
Petro, a former mayor of capital Bogota, has promised to address profound income inequality and provide free public university education, as well opposing expansion of the oil and gas industry.
"I'm here for the proposals he's offering young people," student Viviana Muete, 24, said earlier this month at a Petro rally in the city of Fusagasuga.
Muete, who said she has not always had the money to keep studying, said Petro offers hope that other candidates do not.
Petro will likely face off against either Federico Gutierrez, the center-right former mayor of Colombia's second city of Medellin, or business magnate Rodolfo Hernandez in a second round.
Gutierrez and Hernandez counted on support of 27.1% and 20.9% respectively in a recent Invamer poll.
Gutierrez is supported by a mix of Colombia's traditional political parties and is seen as the ideological heir to current President Ivan Duque. He has warned that Petro would be a disaster for the country's democracy and economy.
"We don't want the left in power, to lead us to disaster," Marta Neiva, 66, said as she waited to cheer Gutierrez at a rally in Bogota.
Hernandez, who is running independently with his own funds, has won support with whimsical social media videos and anti-corruption promises. However, his support may be dented by scandals from his stint as mayor of the city of Bucaramanga and an ongoing graft investigation. He denies any wrongdoing.
Polls will close at 4 p.m. local time (2100 GMT) and officials expect the result around four hours after.
(Reporting by Oliver Griffin, additional reporting by Julia Symmes Cobb; Writing by Oliver Griffin; Editing by Rosalba O'Brien)