Some people think that the Kingdom of God (the Millennium) came in 70 AD, when Jerusalem was destroyed by Titus. These people are called Preterists. In order to believe what they do,
Preterests must believe that the kingdom of God is invisible. The best way to think this is to mistranslate a critical verse in Luke. Here's that verse, and how to translate it correctly so that you don't make tragic/comedic mistake of the Preterists.