St. Martin's Island, locally named Narkel Jinjira (Coconut Island) is the only coral island in Bangladesh. It is home to some rare species of turtles and rare corals that are found only around this island. Countless efforts to preserve this jewel of nature have been suggested, but corals and animals are more and more endangered. This is a very small island, only about 8 square kilometers, so it is possible to walk through the whole island in one day.