Almost four decades ago, Mirabel International Airport was Montreal’s gateway to the world for the Olympic Games. Now it is a decaying, abandoned wasteland facing demolition, after the city failed to come up with a reasonable plan to repurpose the terminal building.

Mirabel still runs cargo flights, but it hasn’t hosted a passenger plane in 10 years.

As the airport’s maintenance costs pile up and the structure begins to collapse, facility owner Aeroport de Montreal says it’s just not feasible to spend tens of millions of dollars to rebuild and repurpose the terminal building. Instead, the company’s board will meet in September to award the contract for its demolition.

The airport will continue to operate cargo flights out of the facility, with the terminal building taking up 15 acres of the 6,000-acre property.

Other derelict airports around the world have been repurposed as parks, hotels and shopping malls, but according to aviation expert Angela Gittens, repurposing an airport isn’t always the smartest choice.

“It’s a very local decision,” Gittens told CTV’s Canada AM on Wednesday.

Gittens, director general of the Airport Council International, said it takes a long time and a lot of planning to repurpose an airport, and sometimes, it’s simply easier to demolish one entirely. “There really is no other use for an airport, besides an airport,” she said.

Mirabel was the largest airport in the world in surface size -- and the most expensive in Canadian history -- when it opened in 1975, one year before the Summer Olympics in Montreal. It had better facilities than the older Dorval Airport, but it lacked convenient highway and transit links to the city, making it a hassle for passengers to commute from Mirabel to the heart of Montreal.

Eventually, airlines began to bypass Mirabel in favour of Dorval (now Trudeau) Airport, and Mirabel lost all its passenger traffic.

Since passenger flights stopped in 2004, Mirabel’s much-diminished facilities have been used primarily for cargo shipping, and as a set for movie productions.

“This area really could not accommodate two major airports,” Gittens said.

She added that airlines hold most of the power when it comes to picking their flight destinations, so there was little Mirabel could do to keep the flights coming in, once airlines decided they liked Trudeau Airport better.

And no matter how modern a facility is, Gittens said a great airfield doesn’t bring in customers – customer demand keeps airports alive.

Ecuador’s former Mariscal Sucre International Airport closed its departure and arrival gates early last year, and has since been transformed into a cultural hub and park. The recently-opened Parque Bicentario boasts cafes, running and biking trails, sports fields, outdoor gyms, museums and areas for outdoor music festivals. Germany, Hong Kong and Greece have also repurposed their old, abandoned international airports.

But Gittens says those solutions were specific to those airports, and they don’t necessarily apply to Montreal’s Mirabel Airport.

“There’s really no one-size-fits-all in these cases,” she said.

Aeroport de Montreal has spent $30 million to maintain Mirabel's terminal building since late 2004, the company said last May. ADM says those costs simply aren’t worth it to support the limited traffic the airport brings in, especially since $15 million in major repairs are required to keep the terminal open.

The Mirabel International Airport cost approximately $500 million to build in 1975 -- the equivalent of about $2.2 billion in 2014.

The following video shows photos from before and after the airport was abandoned.