On the banks of the Patapsco river, hundreds of people from across Baltimore gather in the early evening sun.

Most are taking pictures with their mobile phones and can't quite fathom what they are seeing. The Francis Scott Key bridge, a fixture of this city for half a century, had been destroyed in less than ten seconds.

Through the day, they had watched the pictures on television and seen the CCTV of the cargo ship hitting one of the bridge's support pillars, collapsing the whole structure almost immediately. But many felt they needed to witness it for themselves.

"It's unreal," one woman said, "I actually can't believe it is true, that it's gone." Follow latest: Six missing workers 'presumed dead' Many of those who live on the banks of the river had been woken by the noise of the impact just before 1.30am. Jim Wood's house overlooks the Key Bridge.

"The house shook a little bit," he told me, "at first I thought it was a sonic boom from an aeroplane, I've never heard a sound quite like it, it lasted for six to ten seconds, and then, it was just indescribable." In the distance, a rib boat with flashing red lights circled the wreckage of the container ship and a rescue helicopter circled above. But as night fell, 18 hours after the collapse, any hope of finding survivors was officially extinguished.

Authorities declared this no longer a search and rescue operation. It is now the job of specialist divers to recover the bodies of the six people still missing, all of whom were working overnight on the bridge to repair potholes.

But with dangerous debris in the water, coupled with changing tides, it could take some time to complete. Among those missing is Miguel Luna from El Salvador.

At his house, a family member told me they are distraught as they wait for news. Some of them were taken by police to a location in Baltimore where they could be with the other families of the missing.

All of those unaccounted for worked for Brawner Builders. At a nearby petrol station, their colleague, Jose Campos, is wearing an orange hat and a hoodie bearing the Brawner Builders name.

He does not know where else to wait for news. "My friends were working there, it's a very hard day," he told me.

"My supervisor called me in the morning and told me they had rescued one of my colleagues but he was in a coma. "I never imagined something this awful could happen.

The path where the boat goes was supposed to be a safe zone." The ship had departed Baltimore harbour at 1.04am and was less than half an hour into a 27 day journey to Sri Lanka when it ploughed into the bridge. Crew aboard the ship had issued a mayday call minutes before impact saying they had lost power and were heading for the bridge.

Officials on either side of the bridge reportedly stemmed the flow of traffic, potentially avoiding an even more deadly disaster. "By being able to stop cars from coming over the bridge these people are heroes.

They saved lives last night," Maryland governor, Wes Moore, said. Click to subscribe to the Sky News Daily wherever you get your podcasts Some structural engineering experts claimed that the size and weight of the cargo ship, coupled with the position it struck the bridge, made a total collapse inevitable.

I asked the governor if he believed that was that case. "We're still in the process of investigating exactly what happened," he said, "so we don't have any further details about whether or not it was inevitable but the bridge was actually fully up to code".

While President Joe Biden promised to "move heaven and Earth" to reopen the port and rebuild the bridge as "soon as humanly possible," Governor Moore accepted it would not be easy - or quick. "This is going to be a long-term build," he said.

"We are going to rebuild in a way that remembers the people who this tragedy has impacted, and also do it in a way that honours the community that it serves." The people of Baltimore continue to visit the best vantage point in the city to see what remains of the bridge. There is an element of morbid fascination in it but also the sense that for many it represents the end of an era and a sheer disbelief that the bridge is no more..