Way back, in 1872 a man named Charles Taze Russell had a vision. He foresaw the end of times which would happen in 1874 and invented a religion to go along with it.
He also had other strange ideas about historical events and the size of the Great Pyramid of Giza, such as hundreds and hundreds of links connecting them to the divine and the many prophetic hieroglyphs only understandable by mystics and the adept.
The world didn't come to an end, in 1874 as he hoped. Russell reconfigured his formula in 1891 and declared the end of the world would happen in 1914 and man would be resurrected.
When 1914 come and went and the world didn't end there were a few detractors.
He again foretold the world would end in 1975, which came and went with no doomsday, again a few detractors but the religion survived and continues to this day.
Believer's, of this religion prefer not to talk about these misdirected calculations by there founder but they still keep on promoting the end of times.
Now, when you answer that knock, knock on the front door, and it's them promoting the end of times ask them, When is it going to happen?
They won't give you a date.
Mr. Russell is the founder of the religious sect known as Jehovah's Witness.