Mexico City's Estadio Azteca may be the world's least friendly place to play.
Perched more than 2,000 metres above sea level, with a capacity of more than 100,000, it's the place foreign hopes go to die.
A combination of thin air, heat and hostility has made the arena a fortress for national and local teams. The fans of both are famously ruthless.
After Mexico crushed the United States there in a 2004 Olympic qualifier, home supporters jeered the American team back onto the bus with chants of "Osama, Osama, Osama."
This is probably why nobody paid any real attention when the Montreal Impact advanced to the two-leg final of the CONCACAF Champions League.
Their opponent was Club America. To beat them, Montreal would have to go through the Azteca.
This is the place where Pele stepped off the international stage, and was stripped by his admirers. It's the place where Diego Maradona punched the ball in with his fist and blamed God. It's been host of two World Cup finals. The Azteca is very close to being international football's Louvre.
A team from Canada does not go down to a place like that and do anything but curl up on the ground and wait for the beating to end.
Forget the Azteca for a moment. In 41 attempts, Major League Soccer teams have won only two games against Mexican opposition at home.
It's one of the truisms of soccer – don't go to penalties with the Germans; don't go to Mexico for any reason.
Then Montreal did it.
On Wednesday, the Impact fended off America for 89 minutes, and stood on the cusp of a great victory. The Mexican club got one late. The game ended in a 1-1 draw.
Still, it's a fabulous result. Ridiculous, really.
Put it this way: It shouldn't have happened. Montreal has played four league games so far this year. It hasn't won yet. It is dead last in MLS. And then it goes down to the Azteca and does this. It's staggering.
The Impact now stand on the cusp of making real history. If they win Wednesday's second leg at Montreal's Olympic Stadium, they become the first MLS side to take the Champions League. In its most recent iteration, only Mexican teams have won the trophy.
MLS and its fans like to talk up the league's place in global terms. Is it as good as the English Championship? Or the Danish Superliga? It's certainly nowhere close to the Premiership or the Bundesliga. League officials used to talk about one day matching that standard, but they no longer even pretend.
This week it was reported that Cristiano Ronaldo – the best player in the world just at this moment – wants to come to MLS after his Real Madrid contract runs out in 2018. It's most likely a negotiating tactic, but who knows.
Ronaldo has apparently decided he would like to play in Los Angeles. There will be two teams in the city by then – the Galaxy and the yet-to-be-unveiled LAFC.
Which club would Ronaldo prefer to play for? Either one. He's not bothered. He just wants to live in L.A.
This is not the sort of rumour that tends to burnish the league's image. Instead, it makes MLS sound like a gilded old folks' home – which it absolutely is.
When the world's best players look across the Atlantic, they don't see glory. They see dollar signs. They see nice, clean cities where people don't try to flip your car after you lose on Saturday. They come over here for the good life. Which is a little depressing if you care at all about domestic soccer.
MLS cannot earn their respect by buying it, which is all they've ever done.
In order to truly be taken seriously, MLS has to begin proving it can stand on the field with the best teams from the world's best leagues.
It's never tried, because the only way to do so is by winning the Champions League and advancing to the FIFA Club World Cup. In that competition, they'd play the six other winners of continental club competitions.
So, in very real terms, Montreal is about to put MLS on the global map.
That game at the 'O' is already sold out. Nearly 60,000 Montrealers can't fully capture the Azteca's howling mob, but they can certainly try.
It is fundamentally wrong to cheer for the opposition. Especially so in soccer. Especially especially so when it's another Canadian team. And put a four or a five beside the 'especiallys' when we're talking about Montreal.
Between the Canadiens, the Impact and the conceptual Expos, Montreal's having a bit of a moment. A fork in the thigh would pain me less.
He wasn't a sporty type, but Gore Vidal best captured the essence of fandom in this regard: "Whenever a friend succeeds, a little something in me dies."
But maybe just this once we'll lower the war banner.
The Montreal Impact are about to advance the cause of soccer in the North American context. They're about to stick it to the Americas – both of them. They're about to make a small legend.
That's something we might all be (very, very quietly) proud of.
Cathal Kelly