Is the world going to end and when?

Answer 1

There have been many prophecies of the end of the world. Mark's Gospel attributes to Jesus a statement that the world would end before all those then still alive had died. This did not eventuate, but there were many similar prophecies during the time of the early Church, particularly as the end of the first millennium approached.
In more recent times, Jehovah's Witnesses have often prophesied the end of the world, but each time the world has continued as before. Watch Tower literature persistently claims that the Armageddon will come within the generation of those who were alive in 1914, when Christ returned invisibly to establish Jehovah's Kingdom. As the years go by and fewer of that generation remain, this prophecy must join the list of prior failed prophecies.

The world will undoubtedly end, but not for a few billion years yet.