I need further explanation on the following so I can understand it more completely. I know that the theory of relativity /space and time are connected with the invention of the syncoronized clock and time zone division, and that Einstein originally used train travel to explain his theory (I am assuming this is correct - please tell me if I am wrong). My confusion is trying to explain the hour difference between two cities in relationship to this concept. Can anyone help get me further down my path? (or am I thinking too much? ) Thanks!