Do you remember the Mars Climate Orbiter? It was a probe launched by NASA designed to gather data on Mars. The problem is that the probe never reached Mars. The reason: NASA forgot to convert their measurements from English standard to Metric prior to the launching of the probe.
1914 has been a key date for Jehovah's Witnesses. It is supposed to mark when Jesus was enthroned over God's kingdom, all invisibly of course, and begin the "Last Days" of the generation that would not pass away. How did this date come to be?
According to the Watchtower Bible and Tract Society, it all stems from Daniel's alleged prophecy of tree being cut down and then eventually growing again. 7 times of 360 days of a Jewish calendar from 607BCE to 1914CE. However, much like the Mars Climate Orbiter, we have a data conversion problem.
The Jewish lunar calendar consisted of 360 days, as gathered from Daniel's prophecy. After all, Daniel was an Israelite, so it would only make sense he would prophecy in using his own calendar. However, in October 1582 much of the world adopted and still uses the Gregorian calendar. A calendar that not only uses 365 days a year, but every fourth year adds an extra day, bringing the total to 366 days.
I will freely admit that I am horrible at math, so please feel free to correct my calculations. With that being said I'll let the reader run the numbers.