With its streets lined with restaurants serving steaming bowls of Yunnanese noodles, red lanterns hanging outside homes, and Mandarin as the lingua franca, Mae Salong is more Chinese enclave than Thai town. But there’s a fascinating history of geopolitics, war and the roots of Southeast Asia’s billion-dollar drug trade hidden in the picturesque place in northern Thailand, home to only a few hundred people and high up in the hills of the Golden Triangle, which also straddles Myanmar and Laos.