Hotels & Tours in Cambodia, Vietnam, Laos, Thailand, Myanmar (Burma), Yunnan - Mekong Region, Cambodia, Laos, Myanmar, Thailand, Vietnam and Yunnan (China) Five countries and one province connected by the majestic Mekong river - the unique Greater Mekong Sub-region (GMS.) Steeped in history and rich in culture, it's one of the last travel frontiers with stunning natural beauty and.