NOT LONG AGO, we'd line up at stadium gates eager and excited, decked out in fan gear and ready to tailgate. If we felt any anxiety, it was the healthy kind that breathes life into sports. We always knew, deep in our hearts, the stakes weren't life-or-death.

The anxiety is different now. Many stadiums and sports fields around the world are converted to different purposes. They are field hospitals or coronavirus test sites. Some shelter the homeless. Others are used to feed the hungry. Some are morgues.

But their concrete facades, raised hoops, hardwood floors and green grass remind us of what we had, and of the promise of what's waiting just on the other side of this pandemic.

These are our playing fields.

For the first time in North American history, a state of emergency has simultaneously been declared in all Canadian provinces, all 50 U.S. states and the District of Columbia, and nearly all U.S. territories. Governors across America have mobilized National Guard units to convert field houses, stadiums, arenas and parking lots. The sites include 10 NFL stadiums, along with racetracks and more than three dozen other facilities normally used for basketball, hockey, baseball and tennis, including the site of the US Open, above. They all have new functions now, as the death toll surpassed 50,000 in April.

Staff Sgt. Donita Adams of the Maryland National Guard walks among the sand-colored Army tents surrounding FedEx Field.

"It's surreal," she says. "FedEx Field is something big to us as the home of the Redskins. ... This a totally different atmosphere. Instead of being cheerful and happy and celebrating, we're concerned and cautious."

Like all of her fellow citizen soldiers, Adams has a story about why she volunteered for the National Guard. After a successful basketball career at Glenville State College in West Virginia, she had dreams of the WNBA. Until she missed the final cut for the Los Angeles Sparks. "That hurt," she says. "I just had to pick up the pieces and just find another avenue. And I did."

In the Guard, she found a way to be a basketball coach in her civilian life and a premier athlete in her military uniform. She's on the U.S. Army women's team that won gold against teams from the other military branches, and last October she was one of 12 players chosen to represent America in the Military World Games in Wuhan, China. Weeks after that team took bronze, word came that a new virus had emerged.

Now, instead of getting ready for another season, Adams is among the Guard members staffing a coronavirus testing site outside Fedex that screened more than 800 people over three weeks. "A month from now I would have been at [basketball] training camp," she says. "But at the same time, we understand that this is bigger than us. We're sacrificing everything just to make sure everyone is OK." —Tisha Thompson

WATCH: Donita Adams tell her story

Massive white tents now cover the field of Pacaembu Stadium in Sao Paulo, where a temporary field hospital houses COVID-19 patients in Brazil's most populous city. Doctors there, and across Central and South America, are starting to see a jump in related diseases such as pneumonia. "The amount of testing for coronavirus is quite minimal," says Dr. Kelly Henning, a medical doctor and epidemiologist for the Bloomberg Philanthropies Public Health program. "There's a lot of concern this outbreak is really silently moving forward." Authorities have begun converting sports facilities, including the oldest bullfighting ring in the Americas, to brace for the coming wave.

Pacaembu Stadium is among the most iconic stages in Brazilian soccer. It hosted six matches during the 1950 World Cup, and Pele scored 127 goals here. But in just 11 days this spring, workers transformed it into a 200-bed hospital.

"When I saw the image of the pitch consumed by white tents, it was tough," says Edson Tadeu da Silva, the stadium's announcer for the past decade. "The stadium is a place for fun. Suddenly, it becomes a place of pain, of death."

The 80-year-old venue is in Sao Paulo, a metropolis of more than 12 million and the epicenter of Brazil's coronavirus crisis. Fearing the collapse of traditional hospitals, authorities sought places for emergency care and opted for Pacaembu's central location. The field is now home to 10 wards and 200 total beds, half of which were filled.

Among the 250 construction workers was Flavio Alves da Silva, 46, who once hoped to be a professional soccer player and play at Pacaembu. With this effort, he's finally made it: "I feel like I'm a hero, like I'm a winner." —Rafael Valente and Paulo Cobos

On one of the continents hardest hit by COVID-19 so far, field hospitals stand on the turf normally occupied by the world-famous soccer players of the Premier League and Bundesliga, as well as on basketball courts and rugby fields, such as Wales' Principality Stadium, above. And in ice arenas, there are emergency morgues to house the bodies of the 100,000-plus who have died.

Lee Marchant is a fanatical Southampton FC supporter whose usual job involves fixing up temporary spaces for the United Kingdom's premier sporting events. After the arrival of the coronavirus, he switched to fixing the thermal roofing at a temporary morgue in East London.

"When you get to see it firsthand ... there was the scaffolding ready for coffins to be slid into," says Marchant, 37. "It was really real. I don't think people realize the gravity of it."

Now, he's working on a field hospital at the 74,500-seat Principality Stadium in Cardiff, Wales. The temporary Dragon's Heart Hospital has beds spread across the vast stadium pitch. Marchant helped lay 150,000 square feet of hardboard flooring. Upstairs, patients are already starting their recovery in repurposed executive suites.

Marchant says he was nervous about accepting the job. His uncle has been in intensive care with COVID-19, and he has an 18-month-old son, Theo, back in Southampton.

"The thing which drew me to do this work is that I know I'm helping, otherwise I'd have stayed well away," he says. "It's a massive risk ... but you're playing your part. It's got to be done. I've got my pass so in the future, I can show it to my boy and tell him how proud I was to have worked on it." — Tom Hamilton

Like South America, Africa has yet to feel the full force of the coronavirus. Dr. Amanda McClelland, a public health expert with the nonprofit Resolve to Save Lives, says that's due, in part, to lessons learned from the Ebola virus. "We've seen some really great innovation in Africa's response because of its experience," McClelland says. For example, when Ghanian authorities learned about the coronavirus, they ordered 750 overseas travelers into quarantine upon their arrival. More than 100 were confirmed with COVID-19. McClelland's group has been building emergency treatment facilities and helping African governments plan for outbreaks just like this for 16 years. "Putting COVID treatment centers in a sports arena is a last-case scenario," she says. "A lot of African countries already have Ebola treatment units." Instead, stadiums and fields are being put to use for some of those most at risk, as at Caledonian Stadium in South Africa.

Lucky Manna's family launched the Arcadia Shepherds FC, the first fully professional soccer club in South Africa, in 1903. "We were the first club to defy the government and play players of color," says Manna, the team's owner and general manager. When the pandemic started, the team was in talks with local officials to develop Caledonian Stadium, in the capital of Pretoria, "into a first-class football stadium."

Instead, it was converted into a homeless shelter during the nationwide lockdown. Up to 2,000 people were encamped there, Manna says, with little sanitation or fresh water. "This created a major problem," he says. There wasn't enough food, and tents were unsuitable for rain, prompting many to crowd together in the stands.

Manna says someone stole the goalposts for scrap metal, "and the facility has been wrecked." Government officials, who did not respond to ESPN, eventually moved most of the inhabitants. Some 500 went to Pretoria West Rugby Stadium. "I take food to those stragglers who were left behind every three days or so," Manna says. "There are about 11 who still reside in the clubhouse illegally, but nothing can be done." —Tisha Thompson

READ: More on Manna's plight to save Caledonian Stadium.

Strict social distancing measures and compliance with stay-at-home orders have helped Australia and other Pan-Pacific nations avoid skyrocketing hospitalizations and deaths from the coronavirus. Sports stadiums in Australia are being used as police command centers and to distribute food to those in need. The situation is far more dire across Asia, as the virus exacts massive tolls in nations including India, Iran, Turkey, and into the Middle East. The use of sports facilities as COVID-19 response centers began in China after the world's first confirmed cases appeared in Wuhan in January. Above, a hospital inside a Wuhan sports center. The virus has since spread to more than 210 countries and infected at least 2.3 million people, according to World Health Organization data.

This wasn't how Peter Wright imagined pulling up to Australia's Metricon Stadium on a Friday afternoon in autumn.

The Australian rules football player, a rangy and athletic 6-foot-8, would normally arrive at the Gold Coast Suns' ground, team bag in hand. But, as with just about every other league around the world, the Australian Football League has been halted, and Metricon has been enlisted as a food distribution center.

Wright, along with teammates Touk Miller and Lachie Weller, are volunteering time to deliver meals to those shut in because of COVID-19. Wright and Miller, normally a handy one-two combo around the stoppages, teamed up to deliver meals to elderly club members.

"We just drove out to their houses from the stadium, and left meals on their front step and had a few nice conversations with them about what they've been up to in isolation," Wright says. "It's a very different world to what it was a couple of months ago ... but I guess you have to adapt and make the best of any situation." —Matt Walsh