Why don’t governments start a huge worldwide project to preserve humankind? This may sound insane for many people but it is more insane to keep on waiting until an asteroid causes our extinction. The worst scenario is a massive asteroid hitting our planet causing enormous tsunamis to wipe out entire cities, dust would block the atmosphere, preventing the earth from getting any sun. Plant life would become extinct, and a nuclear winter would begin .Maybe a deadly impact is unlikely to happen soon but we cannot put at risk our existence in the hope that a megadisaster will never happen. This is no joke. We have to build underground cities (nuclear powered - artificial light to keep plants growing to provide food and oxygen, etc.). A HUMAN PRESERVATION PROJECT must be initiated.