The 1,350-mile-long Irrawaddy (or Ayeyarwady) originates in the Himalayas at the confluence of two rivers in the northern reaches of Myanmar near India and China and winds south before emptying through a vast delta into the Andaman Sea; its main tributary is the Chindwin River. Classic 10- or 14-day Irrawaddy River itineraries travel between Yangon on the southern coast and Mandalay in the central region while shorter versions ply the 110-mile stretch between Mandalay and Bagan, an ancient city carpeted in pagodas and temples. Most Irrawaddy cruises operate between August and April — with October through February the coolest (relatively speaking) and greenest period — and many lines are on hiatus from May to July when it’s extremely hot and dry and river levels are very low.