Tuvalu has four reef islands and five true atolls. The atolls have only 26 km of land. Tuvalu is the fourth smallest country in the world. The land is very low lying and the coral atolls are narrow. Funafuti is the largest atoll of the islands and atolls. It has many islets around a central lagoon. This is about 25.1 kilometres (15.6 mi) (N–S) by 18.4 kilometres (11.4 mi) (W-E), centered on 179°7’E and 8°30’S. A