~~ Historical Accuracy ~~
There are no unbiased, extra-Biblical, historical accounts of Jesus' miracles written while he was alive. Written accounts were not put down on paper until decades or even centuries later. For someone who performed miracles, walked on water, and rose from the dead, the basic expectation is that at least a few historians from that time would have noticed these amazing events and written about them. Perhaps it has something to do with the fact that miracles like resurrection were fairly common up to this point in history. Osiris, Horus, Asclepius, Achilles, Lazarus, and the daughter of Jairus were all resurrected and they were not all divinely-conceived. As human knowledge has advanced, resurrections have declined. Infer what you like from that fact.
There have been many debates on the historical accuracy of Jesus' resurrection. Sufficient evidence does not exist to persuade everyone of the event's historicity; however it is safe to say that without the resurrection, the religion we know as Christianity would cease to exist. The resurrection of Jesus hinges completely on eyewitness testimony, but unfortunately eyewitness testimony is not as reliable as some may commonly believe. In fact, from a neuroscience perspective, it is incredibly unreliable. As we now know, human memory is malleable and prone to mistakes. As it relates to the resurrection, there was far less "eye"witness testimony and more "ear"witness testimony. The Gospels are our only source of "evidence" for the resurrection with particular attention paid to Mark's Gospel as it was the earliest of the four gospels. If I reference Thomas and Peter being visited by Jesus, this account is not coming from an unbiased source. Everything is coming from the Bible, so frankly it doesn't matter if 1 person said they saw Jesus or 500 people did. The number of witnesses becomes irrelevant if it can't be corroborated. The Bible could make the claim that every person on Earth was personally visited by Jesus and the same problem remains. This is all being reported according to a single source: the Bible - hardly an unbiased source of historical accuracy.
Not only is the Bible biased, it's contradictory. The Gospels cannot even agree with each other on details surrounding such a monumental event. For example, John tells us that Jesus died the day before the Passover meal was eaten but Mark explicitly says that he died after. John says he died at 9:00 in the morning. Mark says it was noon. After his resurrection, did the women rush out to tell everyone what happened? Matthew, Luke, and John say "yes", however Mark says "no" (16:8). Could the faithful physically touch the resurrected Jesus? John says no (John 20:17), yet in Luke we have Jesus appearing to the disciples and saying "Look at my hands and my feet. It is I myself! Touch me and see; a ghost does not have flesh and bones, as you see I have." (Luke 24:39) Did Simon of Cyrene carry Jesus' cross or did Jesus carry it the whole way? What did Mary, or Mary and the group of other women, see in the empty tomb? Was it one man, two men, or an angel? Where were the disciples supposed to go see Jesus: Jerusalem or Galilee? The answer to each of these questions depends entirely upon the Gospel that is being read. The Bible purports to describe a historical event, however the contradictions within it are real and they are undeniable. If we give historical weight to Jesus' resurrection simply because it is written in the Bible, we must also give historical weight to Matthew 27:52-53 which tells us that the moment Jesus died, the tombs of all the dead saints broke open and the inhabitants rose alive and physically walked around town where people could see them. Surely this event would have been worthy of a sentence or two by any one of the Jews who allegedly witnessed it, yet unbiased third party accounts of this event do not exist. We can find non-Biblical sources that make reference to Jesus, his baptism, and his death but we have to rely on the Bible for the resurrection. Resurrections and dead people walking around town are far more impressive events and yet authentic, contemporary, non-Biblical texts corroborating these events remain elusive. To highlight the contradictions, I would challenge any Christian to give me an accurate description of the events that occurred between the resurrection and the ascension of Jesus. Using just the Gospels, any believer should be able to give me a plausible, coherent account of events surrounding what is arguably the most important moments of Christianity. The only caveat is that the believer must use all of the details from the Gospels. This seems like a relatively easy task for a text purported to be the inerrant and infallible word of God, and yet it is impossible. Try it for yourself. Read the Gospels as they are written and in context. It's an interesting exercise. The many contradictions make it impossible to deliver a coherent, plausible narrative of the resurrection without ignoring parts of each Gospel.
The determination of whether or not Jesus was resurrected is not the point behind highlighting the contradictions. The contradictions themselves do not disprove the resurrection, but they should cast serious doubt upon the available evidence. In what is an already biased and interpolated collection of ancient texts, the unsubstantiated and uncorroborated assertions are more than just troublesome particularly because of the extreme significance of the resurrection portion of the narrative. Nobody makes this clearer than Paul (I Corinthians 15:14-15) when he says that if Christ was not raised, then Christians are false witnesses. Their preaching and, more importantly, their faith are useless. With such a monumental event as the resurrection and ascension of Jesus into Heaven, we should be inundated with contemporary sources vanquishing any possible doubt of the event's historicity and yet doubt and skepticism are far more intellectually honest than blind faith in this matter.
The resurrection isn't the only topic upon which to cast doubt. There isn't a viable historical account outside of the Bible claiming that Herod ordered the slaughter of all the infant boys in Bethlehem because he was afraid of losing his throne to the newborn King of Jews. No conclusive evidence exists of this infanticide. Jesus' triumphal entry into Jerusalem where he is welcomed by crowds of people laying their clothes on the ground never warranted a mention by non-Biblical contemporary sources. When the veil separating the Holy of Holies was torn from top to bottom at the moment that Jesus gave up his spirit, surely a contemporary Jewish historian would have found the spontaneous tearing of a 60-foot, 4-inch think veil in such a significant Jewish location to be worthy of mentioning. It's one thing to make a theological claim. It's something entirely different to make a historical claim. The latter has a higher threshold of proof.
Scholars have looked for unbiased, contemporaneous sources to support the gospels, but nothing worthy or authentic exists. Philo of Alexandria was a Jewish philosopher who lived during the time of Jesus. He was responsible for dozens of writings and never once does he mention Jesus. If there was any Jew who would have taken a profound interest in the Son of God, Philo was it and yet Jesus (and all of his miracles) never even became a blip on his proverbial radar. The Jewish historian Justus of Tiberias lived in the decades immediately following the crucifixion and never once mentions anything about Jesus or the influence of his followers. In the following decades, we find scarce mentions of Jesus from Roman historians Suetonius and Cornelius Tacitus and neither historian makes any sort of divine reference. The only somewhat contemporary source we find divine reference to Jesus is in the Antiquities of the Jews, written by Flavius Josephus sixty years after the death of Jesus. In it, Josephus makes reference to James (the brother of Jesus), John the Baptist, and the resurrection of Jesus. The Testimonium Flavianum describes the story of Pontius Pilate condemning Jesus to the cross, Jesus rising on the third day, and the continuation of the tribe of Christians. There is broad consensus that the references to James and John were authentic, however the consensus among both Christian as well as secular scholars is that the Testimonium Flavianum may only be partially authentic. As has happened many times throughout history, later Christian interpolations "enhanced" the authentic nucleus of the story. Most scholars believe that Josephus tried to write a historical account and the original work was likely neutral until its modification sometime between Origen and Eusebius. Minus the forged Josephus account, there does not exist a single unbiased, contemporaneous source to corroborate the resurrection.