The Yeti is really just stories of the Gigantopithecus reaching modern times. A creature that is documented in the fossil record and definitely existed possibly as recently as 100,000 years ago. LIkely wiped out by our ancestors it is remotely possible that they have a terrible fear of humans and a small colony survives. However they have been discovered albeit discovered dead. So this one surely is the answer.
http://en.wikipedia.org/wiki/Gigantopithecus
Also alien just means foreigner someone not from the country they are living in. It has come to represent lifeforms from outer space but that's not its true definition. So they have already been discovered too.
If your a religious person then surely you accept god has been discovered already as there are stories of many people communicating with god in the bible. Of course it has no basis in reality and not a single supporting fact but if you do believe in god then surely you believe what is written in the bible.
