I could not choose just one on the poll. Everyone of those are very real threats that could happen anytime maybe even today right now this very second. Even a mistake on the Nuke radar could have us sending nukes over to russia thinking we are under attack and in reality we are not, it has almost happened twice now. And with the Human race LONG LONG LONG over due for a massive plague something is going to break i can promise you that, it is only a matter of time now. Sad thing is you probably wont even know about it until its too late. the media wont report it in fear of causing mass panic. so just be ready for anything.