Football? Rugby?

I received a question regarding the differences between these two old sports. In many parts of Asia, as well as North America and Australasia football is referred to as "soccer". This is not the traditional name however. "Association Football" is an official name given to the sport originally thought to have its origins in the Uk, but may in fact have first been played in China!! Rugby, on the other hand has the official name "Rugby Football" and the RFU (Rugby Football Union) has it's headquaters at Twickenham, in London.