A former leftist guerrilla and a millionaire businessman will go head-to-head on Sunday hoping to become the new president of Colombia following a tense campaign in which no candidates appeared safe.
Gustavo Petro, 62, comfortably topped last month's first round of voting and is vying to become Colombia's first left-wing president.
But Colombia's traditional political elites have thrown their weight behind his unconventional independent rival, 77-year-old construction magnate Rodolfo Hernández.
The most recent opinion polls have been inconclusive, meaning a tight race lies ahead.
A self-styled "revolutionary" warrior for the marginalised – black and Indigenous people, the poor and the young – Petro promises to address hunger and inequality.
Accused of despotic tendencies while serving as mayor of Bogotá from 2012 to 2015, Petro is in his third presidential race.
The father of six is described as a good orator, though not necessarily charismatic. He is a map buff, and a keen social media user.
Born into a modest family on Colombia's Caribbean coast, Petro embraced leftist politics as a teenager after the 1973 coup d’état in Chile that unseated Marxist president Salvador Allende.
He joined the M-19 urban guerrilla group as a 17-year-old, but insisted afterwards that his role in Colombia's decades of civil war was as an organiser, never a fighter.
Petro was captured by the military in 1985 and claimed to have been tortured before spending almost two years in jail on arms charges.
He was freed and the M-19 signed a peace deal with the government in 1990. He has since served as a senator and mayor.
Petro's critics have sought to portray him as a radical populist who will bring about Venezuela-style economic collapse.
He has, however, railed against the "banana republic" rule of Colombia's neighbour and vowed there would be no expropriation on his watch.
In a country with a tradition of political killings, Petro travels in a convoy of a dozen armoured vehicles accompanied by police on motorcycles, an ambulance and snipers.
He has said he would reopen negotiations with Colombia's last guerrilla group, the ELN, and seek to peacefully dismantle the drug trade.
He has made it his mission to address climate change, somewhat controversially by phasing out crude oil exploration – a major income-earner for Colombia.
Dubbed by some as the "Colombian Trump," independent candidate Hernández sprung a surprise to reach the second round.
A millionaire maverick, he has already ripped up the traditional election campaign book with a series of leftfield policies and clumsy gaffes.
From vowing to close embassies around the world to pay off student debt, to making sport and taking to the open sea compulsory, Hernández is anything but conventional.
He has run his campaign almost exclusively on social media – he calls himself the "King of TikTok" – and shown a willingness to perform 180-degree policy changes mid-campaign, such as first supporting and then opposing fracking and the destruction of drug crops with chemical spraying.
He ran on an anti-corruption ticket, branding the traditional politicians as "thieves" only to receive their support once he had beaten their candidate Federico Gutiérrez to the second round.
"I take votes wherever they come from, but what I don't want is to receive orders," he said.
Despite his anti-corruption stance, Hernández is himself facing a graft investigation from his time as mayor of the northern city of Bucaramanga, over the awarding of a US$143-million rubbish collection contract to a company linked to his son Luis Carlos. He is due to be tried on July 21.
It was during his 2016-2019 mayorship that he also made his most alarming gaffe, declaring himself live on radio as "a follower of the great German thinker Adolf Hitler." Prompted by the station hosts, he somewhat unconvincingly claimed to have mistaken the Nazi leader for Albert Einstein.
"He drinks ... from annoyance with the traditional political class, from communicating in a simple way using colloquial language ... and of course falls into the world of populism," Angela Rettberg, a political scientist at Los Andes University, told AFP.
Hernández claims to be worth US$100 million having made his fortune building affordable accommodation in the 1970s.
He says he wants to "end poverty, without getting rid of the rich" and has vowed not to accept his salary and slash political expenses.