
January 1, 1970 you will be greeted with an easter egg of a retro Apple logo on your screen.
Resetting your date to this extreme will basically brick your device and at this time Apple does not have a fix for it - but they are working on a fix for an upcoming software update which has not been announced for a release date.
For now, if you have become one of the unlucky ones to fall for this trick, the only remedy is a visit to the Apple Genius Bar and most likely they'd replace the device.
This issue affects most newer devices: iPhone 5S, iPad Air, iPad Mini 2 and newer.
So unlike what the Nike commercials tell you, this time - just don't do it.
For more information, please visit the Apple Support site for this issue:
https://support.apple.com/en-gb/HT205248