The foundation of the Christian faith is the resurrection of Jesus Christ. As important as the crucifixion is, the reason we know that was something more than a senseless death is that Jesus rose from the dead. The Apostle Paul tells us that if Jesus did not rise, our faith is in vain.
One of the great defenders of the resurrection is apologist William Lane Craig. In this video, Craig speaks to the historicity of the resurrection. You can find more resources at the Reasonable Faith site.