Spreading out into the Bay of Bengal and across the border into India, the Sundarbans are surely one of the greatest natural zones in Asia. They cover a whopping 3,900 square miles in all, claiming vast swathes of Bangladesh's coastal flats for their untamed patchwork of mangrove swamps, lazy riverways, mudflats and brackish creeks. 

Everything from daytrips to intrepid multi-day safaris are offered by Sundarbans tour guides, many of whom can be found in the nearby towns of Khulna or Mongla. Those adventures typically include stops at the UNESCO reserve's wildlife center before delving into the rivers and the Sundarbans proper. It's there where you'll stop at famous Hiron Point – known for its population of proud Royal Bengal Tigers – and Tin Kona Island – a speck of marshy mangrove where deer stalk the groves with tigers in tow. 

A visit to the Sundarbans can also help reveal the human history of south Bangladesh and the Bengal region. Stilted villages and muddy hamlets pepper the fringes of the park. They host earthy taverns that sell fish curries and freshwater catches, offering a unique glimpse at life on one of the world's largest mangrove forests.