What is at the beginning of eternity? This one's easy. Eternity has an infinite value attributed to it, which means that it is that which is boundless and to be boundless it cannot have any finite value. Two characteristics that would simply would not exist in an infinite value are a beginning and an end. In other words, Eternity, by definition, would not have a beginning or end.<br />
The end of space and time could only ever come to pass if it existed inside in a finite fr<x>amework but there is another point to this that will serve only to complicate the problem, and it's this: at the moment of the universe's birth, time itself began. Now, think about this very carefully: because time began at the universe's birth, it does not make sense to ask "What came BEFORE the Big Bang"? The word 'before' is a temporal term that makes it possible to catalogue, place and make sense of 'when' something happened. The upshot of all this is that there was no 'before' the Big Bang.<br />
The third part of your question seems to allude to something that is called a cyclical universe and there really isn't enough room to discuss it here. Content yourself with the other two answers that I provided and if you really, REALLY want to know more about a Cyclical universe then Wiki it ok? Hope this helped.
*yawns* the letter E
INSIDE THE TARDIS
Anyone fancy a pint?
without it life cannot be formed, it is in your heart but not in your body
First of all, the beginning of eternity is an oxymoron. If you have eternity, you cannot have a beginning or end. And yet, there is a truth to that statement too. What is at the beginning of eternity?--God was there. He started this world with the Beginning. Jesus was there. He is the Beginning, the active cause as Colossians 1:8 says He was. "And He is the head of the body, the church; He is the beginning and the firstborn from among the dead, so that in everything he might have the supremacy." (I wish I had the ability to underline and bold some words.)