Eat it up, Marty McFly. A tunnel in Guizhou has been reported by several people as having the ability to actually turn clocks back an hour simply by driving through it (sans Delorean), according to the Global Times.
The 400 meter tunnel has been receiving so much attention for its time-changing effects that one reporter with Gui Yang Evening News decided to test out the phenomenon: eight out of 10 times, his mobile clock went back an hour.
Time travel is now! Think of all the hilarious misunderstandings that will ensue!
Except not really. After driving further away from the tunnel, the clock eventually returns to the normal stream of time (Universe A).
Mobile phone clocks are set based on time codes embedded in wavelengths that are sent from nearby transmitters. Rocket News 24 explains:
In this case, someone driving into the tunnel will be connected to a transmitter on that end giving the data of 4:35 pm. When the tunnel is entered (assuming it’s not hooked up with a signal) the connection drops out. Finally, when they exit the tunnel, the mobile phone connects with the nearest transmitter and updates its clock with that data [3:35 pm].
It would seem that someone botched up the time setting on that particular tower or mounted antenna causing it to send out the incorrect time. That’s why when you continue driving out of its range the clock returns to normal.