There's no mystery why Colombia produces great climbers - it's got a long tradition of cycling and most of them live their lives at altitude and are used to riding steep hills and long distances - I really recommend Matt Rendell's book, Kings of the Mountains, for the background. Quintana has been regarded as the top emerging talent from Colombia for a while now. And Henao was no secret even before Sky recruited him. I mean, sure, they could all be dirty drug-taking cheats but there is certainly no more reason to suspect the Colombians than the Australians or the British.