Joint U.S. and Canada Mission to Asteroid Bennu
There are many ways that the world could end. War, volcanoes, plagues, solar flares, etc. One disaster scenario that has gotten a lot of publicity is the possibility of a big asteroid strike that would destroy civilization. There have been attempts to catalog asteroids that regularly cross the orbit of the Earth that might pose a risk. There are a lot of that type of asteroid but the probability of any particular such asteroid striking us is very small.