This evidence of a major event you refer to, is any of it outside of the bible?
This is a good point to expound on.
First off, yes there is some completely secular evidence that something pretty significant happened at that place in time. Just the fact that Christianity even exists seems to indicate that something happened to convince some people to change. Also the fact that the early Christians were harshly persecuted for their beliefs, many being martyred and tortured to death. St. Peter was crucified upside down; St. Paul merely had his head cut off because he was a Roman citizen. None of them really gained any material benefits for their beliefs in their lifetimes; someone like Paul actually gave up a relatively cushy life for a life of persecution just to preach the Gospel.
There is also a brief note about Jesus and this event being historical in the secular works of Josephus. It's not a very significant note, but it is there and completely separate from the Bible.
Regarding the other historical evidence, it comprises the Bible itself. The Gospels were not written with the intention of becoming part of the Bible. They were actually written as independent historical accounts. They meet the same criteria we use for other historical accounts from the ancient world. The whole reason they are in the Bible in the first place is because, sometime around the year 400 AD, Christians decided to pull together the best historical material they had about Jesus and canonize it into the New Testament. Until then, there was no real New Testament in the modern sense, just the separate books floating around.
So one of the big misconceptions is that the books of the Bible cannot be historical because they are in the Bible. That is the wrong order of things. The books of the Bible were picked later to be in the Bible specifically because the early Christians got together in councils and agreed that they were reliable enough to go in there.
So the Gospels came first, then the Bible a few hundred years later. It's not like Christians had been around for a few hundred years, realized they needed a New Testament, and had the Pope commission one that would be tailor made to the faith. It was not written that way.
In fact the Gospels actually seem to contradict themselves in certain minor details. For example, it's not totally clear who was the first person to see Jesus when he resurrected. Some parts say Mary Magdalene, some parts say Peter, etc.
These were written independently, and like most independent eyewitness accounts, they don't 100% agree in every single detail. That is usually taken as evidence that they are even more historical, as four historical accounts that are in 100% absolute agreement are more likely to be all written by the same people rehearsing their stories with each other.