Adrian Bridge takes a Mekong cruise through Laos, where, despite the encroachment of the modern world, the ‘Mother of Water’ remains the region’s spiritual lifeblood. My first impression of the Mekong was disappointing. Night had fallen and as we sped north from Chiang Rai to the evocatively named “Golden Triangle” (the meeting point of Thailand, Laos and Burma), I was full of eager anticipation at…