Voters head to the polls in Colombia on Sunday in a historic presidential election that could see the left win for the first time in the conservative South American country. Gustavo Petro, a former guerrilla and mayor of Bogotá, will face off against Rodolfo Hernández, a populist business tycoon and the former mayor of the city of Bucaramanga, in a contest where both candidates have cast themselves as political outsiders. Both men are divisive, gaff-prone and high-handed, and the campaign ahead of the election was bitter, with each candidate accusing the other of corruption. Hernández – who is under investigation for graft – refused to debate Petro and briefly relocated to Miami after claiming his life was at risk. Hernández shocked Colombia when he made it to Sunday’s runoff after ousting a number of career politicians from the race in the first round of voting on 29 May. Petro took the most votes then, some 8.5m, but could not muster enough to pass the 50% threshold required to win outright. Sunday would mark the first time Colombia is led by a leftist. “We are one step away from achieving the real change we have waited all our lives for. There are no doubts, only certainties. Let’s make history,” Petro said in a video shared on social media on Wednesday. “You decide: vote for those who have been embedded in power for more than 30 years or for someone who has worked for their family,” tweeted Hernández, who has eschewed traditional rallies and relied on social media – particularly TikTok – to reach voters. Whoever wins on Sunday will have his work cut out. The country is still recovering from anti-inequality protests that shook the country last year, and the 2016 peace deal with the leftist Revolutionary Armed Forces of Colombia (Farc) hangs in the balance. That deal formally ended decades of civil war that killed 260,000 people and displaced 7 million, though has only been implemented haltingly. But whichever candidate triumphs, history will be made, as both men share their ticket with female Afro-Colombians – meaning that Colombia’s next vice-president will be a black woman. Petro’s running mate, Francia Márquez is a rural activist who won the prestigious Goldman environmental prize; Hernandez’s partner on the ticket is Marelen Castillo, a little-known university director and conservative Catholic. “One of the things that makes this election stand out is that it draws apart the traditional political forces that have been waging power in the country for two decades,” said Sergio Guzmán, an analyst who runs the consultancy Colombia Risk Analysis. “It’s a stark departure from where the country has been and it leads to an uncharted path.”