COPENHAGEN, Denmark -- Ulrich Ammundsen was stunned and confused about what he had seen and what he was feeling and what he was supposed to do. Christian Eriksen, the star player for Denmark, had collapsed on the field just before halftime of the team's game against Finland. Watching from the stands, Ammundsen saw the player crumple, saw him looking limp, saw his teammates circle around him as the medics pushed on his chest.

When Ammundsen arrived home here very late last Saturday night, he found himself staring into his bathroom mirror, unable to process what had happened a few hours earlier.

Even after Eriksen was taken to the hospital, and even after word came that Eriksen was alive and stable, Ammundsen -- who is a host city manager for the fan zones in Copenhagen -- struggled to process his emotions. He wanted to say something, wanted to express something about how he felt for Eriksen, wanted to tell Eriksen how much his incredible success means to Danish people. Wanted to make clear how hard he had wished for Eriksen to stand up again.

Ammundsen just didn't know how. So that night, as he finally drifted off to sleep, still turning over in his mind the roller-coaster of emotions he had experienced, he came up with an idea. There is a wall at the fan zone, he told his wife in the morning. Eriksen's picture is already on it. What if the wall, he said, was turned into a giant letter to Eriksen from every Dane who wants to sign it?

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He drove to work. He told his colleagues. Everyone loved the idea, thought it would be meaningful and therapeutic. Then Ammundsen realized they didn't have any markers and hurriedly called his wife to ask her to pick some up. She went to the supermarket and dropped them off at the office near the port, and early on Sunday morning, the first person -- a man who by chance was at the fan zone with a group of heart attack survivors -- picked up a marker and wrote Eriksen a message. Then another fan did. And another. And another.

Ammundsen stood back and watched. "I wanted to give everyone a chance to send a message," he says now. "And here it is."

There is so much that still remains unclear about that Saturday, so much we don't yet know even as Denmark prepares to play again, against Belgium here on Thursday. What happened, exactly, that led Eriksen to suffer cardiac arrest? And after medics were able to heroically resuscitate him, what does it mean for his life going forward?

Those questions will take more time. What we do know for certain is the depth of feeling that rippled through this entire country as soon as Eriksen fell. Soccer here is a point of incredible pride for Danes, and Eriksen's success -- first with Ajax in Netherlands, then Tottenham in the Premier League or this past season with Inter Milan in Italy -- has long been something Danish fans could revel in. To have Eriksen -- born, in 1992, the year Denmark won their only Euros, in the small town of Middelfart -- leading the team in this tournament, where Denmark is able to play Euros games in its home stadium for the first time, was a source of national joy.

Then, suddenly, that happiness was cut. Patrick Hoff Sonne, a 32-year-old Danish fan, was sitting a half-dozen rows from the field on the side where the incident took place, and he says he initially thought Eriksen might just have fainted or felt woozy because of dehydration. That lasted only a few seconds, though, because once the doctors began performing CPR, a horrible silence fell over the stadium -- "a graveyard silence," he says -- and Sonne felt sick.

"I saw Christian Eriksen's girlfriend" just a few rows away, Sonne says, and she was "carrying [one of] their children in her arms." A friend Sonne was with had recently had a child himself and began crying beside him. Sonne felt trapped. "I had to look away from the situation there."

Sonne left the stadium. He had to get out, he says, even once he heard that Eriksen was awake as he was taken to the hospital. For Sonne, the shock, disbelief and fear had all mixed together, and though there was a chance the game might continue (it eventually did), Sonne knew he was in no place to cheer.

In the days since, he has grappled, just as Ammundsen did, with how to come to terms with seeing a person he has strong feelings for in such a grave state. Thomas Delaney, a Danish defensive midfielder, has said that he and his teammates have taken great comfort in talking openly with each other about how they're feeling ("We've all been struggling differently in our own ways"), but Sonne is among those who have preferred to avoid talking much about the situation.

"I'm trying to stay away from the updates and social media and everything," he says. "I haven't seen the wall yet."

He tears up. "I haven't been able to write on it."

One day earlier this week, a husband and wife approached Ammundsen in front of the wall. They had a picture in their hands and wanted to tape it up. Ammundsen asked what it was, and they explained that their son-in-law was one of the medics who had rushed onto the field to save Eriksen's life.

The photo was a picture of him leaving for work earlier that day, hours before the match began.

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"When he got home that night, his 6-year-old was already sleeping," Irene Dahl explains. "The next morning, when she woke up, she told him, 'Daddy, you're my hero.'"

Ammundsen walked them over to the wall and showed them the markers as they taped up the picture. A grade school teacher, Pernille Hansen was also taking a moment to sign herself while some of her students were playing on the tiny soccer field nearby. She had seen the game, of course, but even more she had come into school on Monday morning and heard her students, most of whom are 14, talking to each other about what had happened. Some of them had come straight to the wall that day.

"It's a big deal," she says. "Some of the students were a bit afraid and it's important to talk about it. It's important for me to write this message. He's a brilliant, brilliant football player, but he's also a [partner] and a father. And we can all relate to that, can't we?"

Standing nearby, Ammundsen nodded. Hansen went back to her kids, but soon another man came past. Then a group of teenage boys. Another group of students. A businessman on a break.

The messages have already overflowed around a corner from the original wall, and soon, Ammundsen says, they will have to take down some Heineken advertising panels to make room for even more.

"We were all affected by what we saw," Ammundsen says. "It was very emotional."

He smiles. "We'll get as many markers as we need."