Whoever thought that shirt-swopping happens only on a football pitch should probably visit Rio de Janeiro's Copacabana beach.
There, on the white sand and with the Atlantic Ocean as a backdrop, fans from all over the world trade high-fives, football stories, rounds of beer and, yes, even shirts.
Argentinian Paul Mengon had never met German Dietmar Seufzer. But when it is World Cup season, anything can happen.
Said Seufzer, 47, who is in Brazil with a small group of friends: "We were sitting next to these guys in the bistro, exchanged greetings and than came the suggestion to swop shirts.
"I thought: 'Why not?' "
So he took off his Bastian Schweinsteiger jersey and Mengon his Lionel Messi one and both took part in a ritual that is usually carried out by players.
But with the spirit of goodwill and camaraderie in abundance on Copacabana, as with the caipirinha (Brazil's national cocktail), it is not uncommon to see fans of different countries mixing like long-lost buddies.
"It's one big amazing party, a daily party for one month," said Mengon, 46, who has been in Brazil since June 11 and managed to get tickets to all four of Argentina's games so far.
Added his friend Tomer Tpinkusiewicz, who is of Polish-Argentinian descent: "It's just such a great atmosphere.
"You meet an average of about 50 people every day, from different countries.
"I've met people from Luxembourg, Zimbabwe; I've probably met at least one person from every continent so far."