There have been many fine responses to your post. But I wonder if you have heard there are newly discovered fragments of Mark that are being dated to the first century. This would place them within the lifetimes of some of the physical eyewitnesses of the ministry of Christ. See more info here:
http://www.hughhewitt.com/transcripts.aspx?id=2ae35594-18e1-4776-bd4a-ca8f77c4deb6
Also, something to think about. Let’s say there was a person called Jesus, and he taught many good things, but was killed by the religious/political establishment of his day. Now picture yourself as one of his disciples. Jesus has just been killed, and the authorities might being coming after you next. What do you do? Hide in fear? Probably.
But now let’s say something happened, something so amazing it changes you, changes you and every one of your fearful, sorrowful, hiding companions into men and women with the boldness to go about in public preaching Jesus as the savior of humanity. What would it be like, really, to see him alive again, after having seen him killed on the cross? Would it not have exactly that effect? Wouldn’t your fears melt away and give way to an irrepressible joy you could not contain? Would you not then know that death really was not the end, and you could face it with confidence?
It is one of the most difficult problems faced by those who would discredit the existence of Jesus, or failing that, the claims of his resurrection. There is simply no easy way to explain how the disciples survived that first lethal blow. There should have been nothing left but cowards running from the destruction of their failed leader, who seemed to promise messianic revolution, but was now dead and cold in the tomb.
Instead, there was bold and convinced proclamation of an impossible fact, first a dozen, then hundreds, then thousands and more, all within the space of a few short months, an explosive increase of people willing to believe, preach and die for a man who, they said, had risen from the dead.
If it was false, and the establishment wished to stop this new religion in it’s cradle, why not simply discredit the lie that there even was such a person? But that was never attempted or even questioned. Why not? Or if he was, as everyone knew, quite real, why not produce the body? The authorities had the motive and the resources to do so, and if Jesus’ body was available, they certainly would have done so. It was bad politics, for both Rome and Israel, to let this thing go unchecked. Yet they could do nothing to stop it.
The most natural explanation is that something remarkable happened to turn things around for those first beleaguered disciples, something that corroborated everything Jesus had taught them, something very like a resurrection.
Food for thought...
And nobody ever came forward and said, “This is ridiculous. Let me show you Jesus’ body. It’s right here in this tomb. We have Roman soldiers making sure it’s right where it’s supposed to be.”