How do you KNOW that God exists?

You cannot see natural gas. It is odorless (they add odor to it so you can smell gas leaks), tasteless, invisible, etc. You only know that it exists because it can produce fire. You also cannot see the feeling of love. You can however see evidence for this emotion. The same is true with God. You cannot see him because He is invisible, however you can see plenty of evidence of Him. He has done many miracles in my life. He has changed my life and millions of other people. There is also the Bible, where God speaks to people about who He is.