The air is thick with “Siiiiiiiiuuuuuuuuuuuuuuu…”The sound of Portugal fans repeating Cristiano Ronaldo’s signature goalscoring cry will be familiar to anyone who has attended any of their games at this World Cup. Or indeed, any of their games anywhere.It serves as a sort of monosyllabic call and response. Someone yells “siiiiuuuu”, then any fellow admirers within earshot respond with “sssiiiiiuuuuu”, then anyone who didn’t hear the first one will yell “ssssiiiiiuuuuuuu”, and it all starts to echo around your head, as if you’re in a cave and all you can see are people wearing a No. 7 Portugal shirt.But it’s not just during games. It’s before games, after games, on days where there isn’t a game. You hear it in bars, on the train, walking down the street. A few hours after Portugal beat Uzbekistan 5-0 in their second group game, Pinkerton’s BBQ in Houston is full of people in Ronaldo shirts, and every few minutes the shout goes up, piercing the atmosphere of mid-level bonhomie.Attending a Portugal game, it’s extraordinary — if perhaps not entirely surprising — just how many Ronaldo shirts you see. It’s genuinely rarer to see a shirt without his name on the back: at points it feels like you’re in football’s answer to Being John Malkovich, only instead of multiple Malkovich heads, it’s Ronaldo shirts.Over two games in Houston, attended by almost 150,000 people in total, I saw thousands wearing Portugal shirts with his name and number on the back, a lower but still significant group with no number on the back and literally two featuring any other player.There was one Vitinha, and one Bruno Fernandes: in comparison to the masses, choosing a double Champions League-winner and the current Premier League player of the year feels like a niche act of wilful obscurity. Like picking a demo version of The Continuing Story Of Bungalow Bill as your favourite Beatles song rather than, say, Hey Jude.The next most common genre is Ronaldo club shirts. Manchester United shirts from both of his two spells (plus one from 2009-10, which was irritating considering he never wore that one). Real Madrid. Juventus. A few Sporting shirts with ‘Ronaldo 28’ on the back, from when he was a teenager. And, relatively rare but still visible, were some from Al-Nassr, his current club in Saudi Arabia.Hero worship in football is nothing new. But the cult of personality around Ronaldo is something else. So much so that a decent proportion of the fans there for Portugal’s games are not there to see a World Cup game, or to really support either team playing, but purely for him.“I’m just here to see Ronaldo,” says Pablo, wearing a 2008 Manchester United jersey. “He’s a legend. I want to see history. Never seen him play before.”Ronaldo fans make their point (Nick Miller/The Athletic)Kevin has travelled from Los Angeles, in his Al-Nassr shirt, and paid $600 for his ticket. “Ronaldo all day,” he says, when asked if he was here to see the game, or to see Ronaldo. Is it a problem that Ronaldo isn’t the player he was? “Not at all! His teammates need to support him more. They’ve played more passes backwards than forwards.”