The edge of the map is a strip of water surrounding the map followed by an invisible barrier in which all players cannot gain access to. This can cause problems as sometimes chests in abandoned mineshafts generate at the edge of the map, causing the player to make and place a new chest next to said chest in order to access all the previously inaccessible items. Creative mode flying does not conserve momentum, meaning if you sprint and stop quickly, you will not drift to another block.