Infinity
Infinity - how did this concept come into existence.This is my take on it.Man as he began to evolve felt the need of numbers, basically some way to count things.Hence various number systems were devised by various human civilizations across the world.So as man started counting, he would have somewhere realized he could go on and on and on forever.With this the concept of infinite would have come into existence.A very very huge number that is unending.He would have started using this concept of endlessness or eternity to other things as well, like our universe, time, etc. Now that we had conceived this idea of infinity we needed a symbol to represent it.So the symbol of infinity slowly came into existence.If you closely observe its basically a twisted closed curve and if you travel across the curve you will realize you end up traveling forever.