evidence: East meeting West, North meeting South: since time immemorial, the Wakhan Valley, in the Pamir Mountains, has existed at the intersection of trails trodden by nomads, peddlers, pilgrims and, at times, the soldiers and emissaries of great powers. When I’d thought about traveling to see this rugged branch of the ancient Silk Road, it had seemed like an adventure to the far-flung periphery of the world. Now, as I looked around the market, taking the long view of history, it felt more like the center. [...] It was here in the Pamirs where Russia’s territorial expansion confronted Britain’s defense of India during the 19th-century geopolitical rivalry known as the Great Game. Both sides dispatched players — maverick officers and ambitious explorers, often in disguise — to chart Central Asia’s wild terrain and win influence. A final flashpoint occurred over the mountain in front of me, where in August 1891 a British agent crossed paths with his Russian counterpart, who claimed it as the czar’s and threatened arrest. Four years later the powers agreed to make that narrow valley between their empires — the Wakhan Corridor — a buffer belonging to neither, and it is still part of Afghanistan, a panhandlelike eastward salient of little importance.