Toni Collins spent some time with a youth football team in Mexico City to find out why Futbol Americano is growing in popularity. (3:05)

How to begin?

It was the best of times, it was the worst of times ...

Nah, this is, after all, about an NFL preseason game between two teams that had gone a combined 11-14-3 the season before.

But it is a tale of two cities. While it lacks the sweep of a great novel, the story does have suspense, mystery, rioting in the streets and selfless deeds.

And it does have some historical significance. This is about the first time the NFL tried to play a football game in Mexico.

The 1968 preseason contest between the Eagles and Lions was scheduled to be the first NFL game in Mexico, but it was played instead in Philadelphia after a late change of plans. Salvatore C. DiMarco, Jr/Special Collections Research Center/Temple University Libraries/Philadelphia, PA

The story is worth retelling if only because the NFL will be back there for the ninth time (third in the regular season) Sunday, when the Oakland Raiders face the New England Patriots at Mexico City's Estadio Azteca -- the same venue where the Philadelphia Eagles were supposed to play the Detroit Lions on Aug. 11, 1968.

Just as the late 18th-century setting of "A Tale of Two Cities" reminded Charles Dickens of the mid-19th century ("the period was so far like the present period"), this story has a familiar ring to the present. Mexico and the United States were both sharply divided internally, trying to weather a storm of protests. Back then, just as now, sports and politics were being thrown into the same arena while the Olympic Games were on the horizon in 1968. In '68, just as in '17, there was even a "Rocket Man."

Maybe the best reason to look back, though, is to recognize some unsung heroes. You may have heard of the names on both sides of the ball -- Mike Ditka, Norm Snead, Tim Rossovich for the Eagles; Alex Karras, Greg Landry, Lem Barney for the Lions. But they weren't the ones who saved the day, who had to move heaven and earth to play that game more than 2,000 miles away and 72 hours after it was cancelled.

That task belonged to people in everyday business attire and work clothes who labored behind the scenes to make sure that the show did go on. People such as Eagles ticket manager Leo Carlin.

"Oh, God, I haven't thought about that game in years," says Carlin, now 79 and only recently retired. "The mere mention of it makes me sweat."

SO HERE WAS the deal. The NFL was feeling the love coming from south of the border. Mexico had its own popular college football teams such as Aguilas Blancas, while the Dallas Cowboys, born in 1960, had developed a strong following.

When the league put out feelers about playing an exhibition game in Mexico City, 10 teams expressed interest. The Lions and Eagles were chosen, and so was a promoter named Jim Oliver. He went all out in the pageantry department, booking a guy with a jetpack named "Rocket Man" to perform at halftime, alongside the dancing Apache Belles from Tyler, Texas, and the Ballet Folklorico de Mexico.

The famed Apache Belles drill team from Tyler (Texas) Junior College was among the entertainment planned for the cancelled game in Mexico City. North Carolina Collection/University of North Carolina/Chapel Hill Library

CBS was set to broadcast the game, shipping down a crew with six cameras, a tape machine and a slow-motion setup. Ticket sales were better than expected for the 105,000-seat stadium; according to one report, sales had reached 70,000 by midweek.

Small problems cropped up, though. Wooden goal posts from the 1940s had to be used. Public relations men from each team had to spend hours showing the grounds crew how to properly line the field.

There were also whispers that the general admission price of 5 pesos (about 40 cents) was so low that, when they did the math, organizers would realize they were taking a bath.

The biggest concern was the mood in Mexico City. In late July, several days of student protests against police brutality had resulted in rioting and deadly violence. There were fears that there might be protests at the game that would not only incite another riot, but also dampen enthusiasm for the Summer Games that were to start Oct. 12.

In an interview with ESPN Deportes reporter Karla Cruz, veteran commentator Jose Ramon Fernandez recalls, "The tension was very strong in that time. The government was afraid that something was going to happen in the Olympics. The situation was chaotic, what with the Olympics, the student movement and a repressive government that used to hide everything."

Ongoing student protests in Mexico City, some of which resulted in violent clashes with police, were a legitimate reason for government officials to be worried that holding the NFL game could lead to rioting. Bettmann/Getty Images

At 2 p.m. on Thursday, Aug. 8, three days before the game, journalists and officials gathered at the stadium for what they thought was going to be a routine news conference. Then Oliver, the promoter, walked in. According to Lions PR man Lyle Smith, as reported by the Philadelphia Inquirer, "He comes over and says, 'Well, the game is off.'"

Mexican authorities had made the decision without consulting Oliver. "I guess they were afraid to get 105,000 people in one place," Smith said. Ricardo Medrano, the general manager of the Federal District Football Association, made the official announcement at 2:30 p.m. The game was cancelled "por fuerzas mayores" -- forces beyond their control.

THERE ARE LOTS of scrambles in football, but nothing prepared the NFL for this one. The parties involved wanted to recoup at least some of their significant expenses. Lions coach Joe Schmidt and Eagles coach Joe Kuharich both felt their teams needed the tuneup. The players, too, were eager for a paycheck that went as high $350 for five-year veterans. Could they rescue the game in just three days?

When the news hit them, the Eagles already had left training camp at Albright College in Reading, Pennsylvania, and had checked into a motel near the airport in preparation to fly to Mexico City early the next morning. "We all had our shots and everything," the Eagles' starting quarterback, Norm Snead, was saying the other day. "We were pretty excited about going. At least I know I was. My only experience with Mexico was Tijuana."

Estadio Azteca sat empty on the day the NFL had planned to play there in 1968, but it was full two months later for the opening ceremony of the Summer Olympics. AP Photo

The first order of business was to find a new venue. The Lions were the designated hosts in Mexico, but Tiger Stadium, their regular home, was occupied by baseball's Tigers. So the game had to be in Philly. On Friday, Aug. 9, under a headline on the front page of the Philadelphia Inquirer sports section that read "Mexico bans Eagles-Lions game Sunday," staff writer Roger Keim quoted Joe King, the Eagles' vice president and business manager, as saying, "If we can't get Franklin Field, there will be no game. John F. Kennedy Stadium is not available. If we do play, tickets will be on a first-come, first-served basis. There is no other way."

To get the University of Pennsylvania's Franklin Field, the Eagles' regular home turf at the time, they needed the clearance of Penn athletic director Fred Shabel, now the vice chairman for Comcast Spectacor. "I honestly don't remember anything about it," he says. "I must have given it to them."

Enter Carlin. He began selling tickets for the Eagles in 1960, fresh out of the Marine Corps. It fell to the young man from North Philadelphia to figure out a way to print and distribute tickets for the 60,658-seat stadium while the clock was ticking.

He did have one thing going for him.

"HE IS THE NICEST man in the world," says Mike Evans, an Eagles rookie in 1968.

"Oh, please, don't embarrass me," Carlin says.

The two of them are sitting in a conference room at the Eagles' NovaCare Complex training facility. Leo is retired, and Mike is the senior vice president of Evco Industries, an industrial supply company, but they are young men again, reminiscing about that '68 team. "Some great players," Carlin says. "Not a great team. Joe Kuharich, the coach, was not well-liked. Planes used to fly over the stadium with 'Joe Must Go' banners."

Leo Carlin, pictured in 1989, started working the Eagles' ticket office in 1960 and didn't retire from the organization until 2015. He was responsible for making tickets available on short notice after the Mexico City game moved to Franklin Field. Bonnie Weller/Philadelphia Inquirer

"I was a ninth-round draft pick out of Boston College," Evans says. "A center because of the size of my ass -- quarterbacks like to hide behind it. Anyway, because I was a rookie, I was just excited to be in camp, never mind going to Mexico City. Some of the guys were happy to travel down there and some were worried about the altitude and the heat. As it turned out, it was hotter up here than it was down there."

"I remember the heat," Carlin says. "That's one of the reasons I started sweating when you mentioned that game. But the other was the pressure. Look, I'm pretty good with tickets. To this day, I can thumb a stack and stop at any number you tell me to -- you want 25, I hand you 25. But this job was crazy.

"On Thursday night, as soon as I heard we were going to play at Franklin Field, I called the Gold Ticket Company with a rush order for general admission tickets. No row numbers, no seat numbers. God bless 'em. I had them by the next day.

"Now we have to distribute them. Five bucks for adults, two bucks for kids. Fans could either go to Franklin Field or to our offices in the Bulletin Building on 30th and Market streets. We set up a great big table in the lobby and start handing them out. I look out at the street, and the line is getting longer and longer. Remember, local games were blacked out then.

"The big problem was this: We had season-ticket holders, people who expected preferential treatment. So we devised a system in which we roped off sections of the stadium, then handed out 3 by 5 cards with the seat locations. It worked."

Mike Evans, a rookie for the Eagles in 1968, said he was "excited to be in camp, never mind going to Mexico City." Philadelphia Eagles

"I just wish the game had gone that well," Evans says.

"Yeah, Norm Snead broke his leg on the first play of the game," Carlin says.

The Eagles lost 20-3 in front of an official crowd of 12,176 -- about what they expected considering the last-minute nature of the game and the heat.

What Snead hadn't expected was the condition of the field. Now semiretired at 78 and selling real estate in Naples, Florida, Snead says, "The grass was dry and pretty gnarly -- it hadn't been properly watered because nobody knew we were going to play a game there. On that first play, I hand off to Izzy Lang for a halfback-option pass that he underthrows and Lem Barney intercepts at midfield.

"He starts running down the field, and I'm thinking, 'Somebody get him, somebody get him.' The somebody turned out to be me at around the 2-yard line. Well, my cleat got stuck in the grass, and I broke my left fibia. I'm lying there with a mouth full of grass in awful pain when the trainer, Moose Detty, and Dr. James Nixon come running over. Right then and there, Nixon snapped my leg back in place. They take me off in a stretcher. X-rays later showed Dr. Nixon set it perfectly."

After the game was relocated from Mexico City to Philadelphia on three days' notice with nary a hitch, Eagles quarterback Norm Snead had to be carried off the field after breaking his leg on the first play. Salvatore C. DiMarco, Jr/Special Collections Research Center/Temple University Libraries/Philadelphia, PA

The one bright spot for the Eagles during the defeat came near the very end of the game. According to Gordon Forbes in the Inquirer: "Most impressive of all the new Eagles was center Mike Evans. He showed his nerve by picking a fight with Lion ruffian Alex Karras."

Evans remembers it well: "I clipped Alex from the back so he wouldn't sack our backup quarterback, John Huarte. Both benches emptied onto the field and the brawl ensued. I was on the bottom of the pile with Alex while he tried to bite me and spit in my face. I snuck out from the bottom of the pile and sat on the bench.

"It took the refs 20 minutes to stop the brawl. Those were the good old days."

Since they fought so hard just to play the game, they might as well have ended it in the same spirit.

AS IT HAPPENED, Snead missed only three regular-season games and led the Eagles to a 12-0 upset of the very same Lions in the mud of Tiger Stadium on Thanksgiving.

Snead missed the Eagles' first three regular-season games after breaking his leg, but he was behind center when Philadelphia met the Lions again on Thanksgiving Day. The Eagles pulled off the upset in muddy Detroit for their first win of the year. Alvan Quinn/AP Photo

Mexican authorities had every right to have been worried. On Oct. 2, 10 days before the Olympics, hundreds of protesters were killed by government forces in the Plaza de las Tres Culturas. During the Games, the raised fists of Tommie Smith and John Carlos on the medal stand brought home the oppression of African-Americans.

Evans would be named the Eagles' offensive MVP in 1971 and played six seasons in the NFL trenches before moving on to take up the family business and the business of family.

Carlin worked for the Eagles until 2015 and was inducted into the team's Hall of Fame in 2012. In announcing the honor, owner Jeffrey Lurie said, "Leo is the epitome of loyalty. He has amazing energy and is always thinking of others."

As for the NFL in Mexico, well, the league returned 10 years later, Aug. 5, 1978, for an exhibition game between the New Orleans Saints and, wait for it ... the Philadelphia Eagles.