For the love of the game called soccer
Some people say you have not really been to Brazil until you have been to Salvador.
It certainly was not on the itinerary of fans following the United States team's progress in this World Cup, who did not expect their team to get this far.
This colourful, musical and historical city is now being descended upon by thousands of Americans, making the most of their unexpected and extended stay in Brazil.
At the city's airport on Sunday morning I met some fans flying in via Miami, while others were making the equally expensive journey up from Rio de Janeiro or Sao Paulo.
Strength in numbers
According to football's world governing body Fifa, more tickets - about 200,000 - were bought in the US than in any other country outside Brazil itself.
Several thousand of those tickets were probably purchased by Mexicans or other nationalities living in the US.
But it shows not only how the game is consolidating itself in the States but also how Americans are prepared to invest serious money following their national team.
Among them are brothers Brent and Pete Lunghino from California.
"We've been in the country for a week or so, seen a couple of games and we just had to come here when the team qualified," says Brent.
He and his brother were wrapped patriotically in the Stars and Stripes outside a Salvador bar watching, along with dozens of locals, the earlier knockout match between Costa Rica and Greece.
"Soccer - it sounds too pretentious if you call it football - is really growing in popularity at home," Pete tells me.
"It's really a global, unifying sport and it's great to be down here among others who love the game."
It is not, of course the first time that the United States have progressed this far in the World Cup but there is a different "feel" to the steady rise of the national team this time around.
Most importantly, fans tell me, the domestic league at home - the MLS - is much more financially robust and well established than during previous attempts to integrate the round ball game into the land of gridiron and baseball.
Most praise for the renewed success of the national squad though has to go to head coach Jurgen Klinsmann.
Klinsmann was one of the most accomplished and famous players of his generation, winning the World Cup as a player with Germany in 1990.
Eyebrows were raised when, on a big salary, he was given the US job and a free hand to reorganise the national squad as he saw fit.
Bringing in several European (mainly German) assistant coaches, physiotherapists and nutritionists, Klinsmann's methods were new and initially frowned upon, particularly when required results did not immediately follow.
Fit and ready
But watching the US squad train here in Salvador on Sunday, they were clearly one of the fittest and best organised teams I have yet seen at the tournament.
It is a healthy mix of younger and more experienced players who clearly get along as a unit and connect on the field - unlike, of course, the England team which never added up to the sum of its parts.
Highly-paid individuals who do great things for their club teams every week do not necessarily fit together into a successful international side.
Led by the brilliant and completely committed Clint Dempsey, this American side clearly believes they can beat Belgium and, for the second time in recent history, reach the quarter-finals of the World Cup.
As Klinsmann barked words of encouragement to his players, I was reminded that before the tournament began the coach had suggested this team was not good enough to go very far.
His controversial decision to leave out arguably the best-known player in the squad, Landon Donovan, also persuaded some US fans that the team was on a fool's errand even before embarking on those "impossible" group matches against Portugal, Ghana and Germany.
Now with Dempsey, Jermaine Jones, Michael Bradley and Tim Howard - under the slogan one nation, one team - the side is hoping to emulate Klinsmann's achievements as a player.
US fans are certainly convinced.
Outside another Salvador bar I met husband and wife Michael and Melissa Pedicolas from Dallas, Texas.
They have also seen several games here in Brazil and are confident the more dedicated approach to the game in the States means this is not just another "here today gone tomorrow" American soccer story.
"Our kids love soccer," says Melissa. "We get involved in promoting and trying to establish the sport at a local level in Dallas and, yes, there's no doubt the game is growing in popularity."
Michael remembers past World Cups when, despite creditable performances and results, it seemed that the folks at home did not really take notice.
"Now it's completely different," he says. "Television audiences have been huge for this tournament, even bigger than the [baseball] World Series. There's a real feeling the country's getting behind the side."
Belgium, of course, finished top of their group after finishing tough matches against Russia, South Korea and Algeria undefeated.
Unspectacular but with a team packed full of experienced players, they are hopeful of bursting the American bubble.
This is the World Cup that keeps on giving and Salvador is a wonderfully passionate, colourful place for such a big game.
Having already played three matches in the heat and humidity of northern Brazil, the US squad will not mind too much another hot and sticky night in Brazil.
A quarter-final beckons and then, who knows?