A World War II photo has resurfaced and gone viral as people are convinced it shows a time traveller amongst the crowd.
If time travelling were real, you might think the powers that be would want to send a James Bond-esque spy to jump through time and carry out missions.
But, ultimately, you'd want someone who could blend in with the crowd. Someone who's discreet. Someone like this guy:
Again, if we were to assume this was legit, then the guy in the image totally blew his cover by appearing to use a smartphone – in 1943.
While there's almost definitely a reasonable explanation for it, a selection of internet sleuths are convinced otherwise.
The throwback photo first went viral in 2016 when Facebook user Kristján Hoffmann shared it on the Icelandic group Gamlar ljósmyndir, which translates as 'Old Photographs'.
He described how the captured scene shows the suspicious man amongst deployed US soldiers in Iceland's capital Reykjavik at the height of the Second World War.
"The American army is taking over Icelandic splendour, as you can see," wrote Kristján.
"One thing that draws attention to this beautiful picture is that above the window, in the corner in the middle of the picture, a man is leaning and is on a cell phone."
As well as the high tech device, the Facebook user also pointed out other unusual details of the 'time traveller', including that he's looking directly into the camera.
"I don’t know what to say, I don’t think he’s just talking on the phone," he added.
"He’s in a stupor, standing alone and wearing a different headdress than the others and a scarf and acting like we would do today."
The image has unsurprisingly sparked a debate online, with many siding with Kristján's viewpoint.
"Solid evidence," wrote one on Twitter, while another said, "The first handheld phone was created in 1983 and WW2 happened in 1930s-1940s... that is time travel wtf."
Others, however, aren't convinced.
A number of people pointed out that the phone wouldn't have worked had it been taken back to the 1940s.
"If I traveled 100 years back in time with a cell phone it wouldn't work because even if I had the phone there would be no cell towers to relay the signals," said one.
Several more realistic theories were put forward, with some suggesting the man was scratching his ear, checking his watch or holding onto a pipe.
As for why he was looking into the camera, maybe he was just curious – or perhaps he liked the attention.
In spite of the non-believers, it seems there are still plenty of people who are convinced of the WW2 time traveller's existence.