Revelation 21:1 Now I saw a new heaven and a new earth, for the first heaven and the first earth had passed away. Also there was no more sea.
Revelation 21:2 Then I, John saw the holy city, New Jerusalem coming down out of heaven from God prepared as a bride adorned for her husband.
John was a follower of Jesus Christ, and had this revelation/vision of things to come on the Island of Patmos.