The hippie trail - a gentle, hallucinogen-powered bus-bound trundle through western Asia from Istanbul to Kathmandu - came into being in the early 1970s. Back then this was an intrepid trip into the almost completely unknown, through places that are largely off-limits to travelers today, such as Iran and Afghanistan, that broadened already-mellowed minds to a backdrop of The Who, Jethro Tull, and Pink Floyd. The birds of this region were similarly...