KHUNJERAB, Pakistan: Finishing nearly 5,000 metres above sea level after hundreds of kilometres winding past blackened glaciers and snow-capped peaks: a new Pakistani race presents a world-class challenge for cyclists — climbing towards the “Roof of the World”.The Tour de Khunjerab — its name a homage to its more famous French counterpart, which began on Saturday — is still many years away from being another Big Loop, but with a solid claim to being the highest cycling race in the world, it has a lot to offer a certain type of athlete.In the last week of June, some 88 cyclists, including two teams from Afghanistan and Sri Lanka as well as solo participants from Spain.