I was reading this Wikipedia article and I reached this part:
Jehovah's Witnesses assert that Jerusalem was destroyed by the Babylonians in 607 BC and completely uninhabited for exactly seventy years. This date is critical to their selection of October 1914 for the arrival of Christ in kingly power—2520 years after October 607 BC.
2520 years after October 607 BC was October 1913. Why did they say it would be 1914?