Thousands of passengers have had their travel plans thrown into disarray after Heathrow Airport shut on Friday.
Homes near the airport were evacuated and some schools shut after a fire at an electrical substation in Hayes, west London, caused a power outage.
The disruption could go on for days, Heathrow said, as it warned passengers not to travel to the airport "under any circumstances" until it reopens.
Passengers who were on flights already in the air have told the BBC of the disruption that ensued after they were diverted to other airports, or turned back to where they had departed from.
Emily Adler was on her flight back from India after a holiday.
She said midway through the flight the captain woke everybody up and said "were on our way back to Delhi".
Speaking from Delhis main airport, she said she and her fellow passengers are in a holding area.
"Weve just been told to wait by our bags, we dont know whats happening next... its just starting to be chaos."
Steve, a businessman, had been on the final stretch of a 14-hour flight from Singapore to London when the speaker system crackled to life.
"The captain came on saying While youve been sleeping there have been some developments", he said.
Their destination - Heathrow Airport - was closed, the captain told passengers, saying that they were diverting to France.
Steve found himself in Paris on Friday morning searching the Eurostar site to get a train back across the Channel, while his fellow passengers contemplated an eight-hour coach ride.
Meanwhile, 3,000 miles (5,000km) away in New York, Danielle, from Shropshire, said she and her parents were left to fend for themselves at JFK Airport after their British Airways flight was cancelled.
Passengers had boarded the plane on Thursday, she said, but were then left waiting on the tarmac.
An hour passed with little explanation, then several more. "We waited four hours onboard to be told the flight was cancelled," she said.
She was calling from the cold, hard floor of the terminal on Friday morning, where they had been camped for several hours.
"No new flights have been found, no accommodation has been offered or is even available to book."
She said among her fellow passengers were "elderly and young children who have been sat on the hard floor for hours."
"We have been issued a $9 (£6.95) food voucher, which will be interesting when a bottle of Evian water here costs $6 (£4.64)," she said.
She counts herself as fortunate. She and her parents had been on their way home to the West Midlands from holiday and had factored in the weekend to recover.
"There is a nurse I am with who has a shift on Saturday, she is now missing out on wages," she said.
"There is another lady missing her daughters birthday party."
As the impact of this shutdown rippled across the globe, some stranded passengers worried that it could take far longer than just the weekend to get home.
In Terminal 4 at JFK, British serviceman William Hastings, 31, camped out, enduring a similar ordeal with a different airline, Delta.
He and two of his colleagues have been away from home these past six months on a military attachment in the US. They were finally on the long way home, setting off from Virginia on Thursday.
While making the transfer at JFK, William saw the tweet from Heathrow Airport saying it was closed. But there was no confirmation from Delta until at least an hour later.
When the cancellations were finally announced to the two Heathrow-bound flights, it was chaos he said.
"Suddenly youve got 500 people rushing [to the bookings desk] to get to these three Delta agents to try and rebook flights," he said.
"People are being told all different kinds of things."
Several passengers from different airports across the globe told of their disappointment over how airlines responded to the disruption.
"They just put some bottles of water, a few packets of crisps, thats it," Mr Hastings said.
"Tired. Frustrated. Angry," is how he summed it up. It was just past 04:00 local time in New York when he spoke to the BBC. He had been up for 18 hours at that point.
He said he and his two colleagues queued for four hours to secure a replacement flight in the end and a hotel organised by the airline - 30 miles from the airport.
Their return flight now is not until Sunday afternoon and they are having to fly via Germany to return to the UK, he said.
"My colleagues and I are now going to Munich but not for two days... and that depends on whether Heathrow is even operational or not."
Have your flights been cancelled, diverted or delayed due to the Heathrow Airport disruption? If so, you can get in touch via Your Voice, Your BBC News.