Watch the Jacques Cartier Bridge light up for the first time

Thousands of Montrealerswatched thecontroversial and costlyillumination of the JacquesCartierBridge,part of Montreal's375thanniversary celebrations, go live for the first time Wednesday night.

It took the collaboration of seven companies, more than2,800 light fixturesand plenty oftrial and error to bring to fruition the $39.5 million project, dubbed "Living Connections,"in time for the city's big bash.

"We've worked very hard to make it happen tonight," said ric Fournier, a partner at Moment Factory, the company behind the project.

• Montreal to stage another Jacques Cartier Bridge light show after police union protest
• What kids hope to celebrate on Montreal's 400th birthday

The bridge lit upin sync with a soundtrack conducted byYannickNzet-Sguinand featuring the Montreal Metropolitan Orchestra.

The soundtrack also featured music by local artists and DJs as part of the show

People who watched the bridge illuminate took to social media with their reaction, marvellingat the spectacle.

Others couldn't help but be impressed, despite the cost.

Many posted pictures from near the bridge.

For some, the light show was enjoyable,but not worth the price tag.

"Beautiful, but it should not have cost $40 million. Feed the poor and then light the bridge," ChristineMarlowposted on CBC's Facebook page.

"It's gorgeousbut why spend millions upon millions of this when there is so much that could have been done with that money to help out city," commented Lisa Vincelette.

While there are skeptics about the project and itshigh price tag, Fournierbelievesit will bring Montrealers together and give new life to the bridge connecting the city to Montreal'sSouth Shore.

"We like to compare it tothe Eiffel Tower with the lighting system," he said. "It has given it another level of attention and, Ithink, attraction."

How does it work?

Every evening, the bridge will become illuminated after dusk.

The square lights will change colours to reflect the season and the mood of the city. They can turn 365 different shades of colour, depending on what's happening at that very moment in Montreal.

"Using a chromatic system, the bridge will always be different from one day to the other, the whole year," Fournier told CBC Montreal's Daybreak.

The lighting control system will gather data from the city weather, traffic and tweets and then reflect them back to Montreal in real time.

"The same as a waterfall:when you look at a waterfall, it's always beautiful, it's always different," said Gabriel Pontbriand, a creative director and lighting designer onthe project.

"Here that was our goal, just to make sure this bridge can be alive."

Fournier said that while the Jacques Cartier Bridge will always be changing colours, organizers have a plan if there is a sudden disaster or death in the city.

"We'll make sure the bridge is not going crazy during a very bad moment," he said.

Fournieradded that he's excited thatMontrealerswill now see the bridge lit up.

"We like to go out, we like to bring people outside and essentially live something together."