On the day of his ascension, Jesus and his apostles walked from Jerusalem to the Mount of Olives (Luke 24:50). On the slopes, Jesus lifted his hands and, while blessing the apostles, “he left them and was taken up into heaven” (Mark 16:19–20; Luke 24:50–53; Acts 1:9–12). The angel told the disciples that as Jesus was taken up into heaven, so would he come back—i.e., visibly. This is one of the reasons why Christians believe in the second coming of Jesus.
The Gospel of John is a very detailed account, but it doesn't come close to divulging all the many things that Jesus did. The Gospel of John says that if everything Jesus did during his earthly ministry was written down, there wouldn't be room enough in the whole world for all the books that could be written. For most Christians, what is written in John's Gospel is sufficient to persuade men that “Jesus is the Christ, the Son of God” so that “by believing you may have life in his name” (John 20:31).