Jesus himself performed many miracles while on the Earth, among them the changing of water into wine at a wedding feast in Canaan, the healing of the blind, the crippled and the lame, the curing of lepers, and even the resurrection from the dead of his friend, Lazarus.
But all of this attracted the attention of the occupying Roman forces, who finally decided that they had to step in when the crowds proclaimed Jesus as their king. Betrayed by Judas Iscariot, one of his Apostles, Jesus was taken before the high priests of the Jews, tried before Pontius Pilate, the Roman Governor, and sentenced to be crucified on the cross.
Also according to Christian belief, the Savior rose from the dead after three days, and was seen to walk the Earth for some time, visiting again his Apostles, before being finally accepted back into Heaven, into which he ascended in glorious triumph, the sins of man expiated, his job on Earth accomplished. He is said to sit there since, at the right hand of his Father. The cross on which he died is still revered by Christians as a symbol of great power and reverence.