What is 4x?
A category of empire management strategy game, typically turn-based, that covers the four paradigms of eXploration, eXpansion, eXploitation and eXtermination.
Some famous 4X games include: Civilization, Space Empires, and Rise of Nations.
Mountain Bike Race with four riders racing is knock out format.
Four riders will race each other down short manmade course with jumps, berms, stepdowns.
4X racing takes place all over the world.
Britain has the largest series in Europe check out nps4x