When will we see the very last sign that we have to see in order for Jesus to return to the earth?

Does anyone know when will we see the very last sign that we have to see in order to know that after Jesus will return to the earth,I am started to think that Jesus is a cartoon character from mythology whom people have made up just like Santa Claus isn't real.It seems like the days are just going to keep going by and nothing will happen and humans will just become extinct one day thanks to a supernova event,what do you think?