MARSHALL ISLANDS. Majuro Atoll. The Marshall Islands are a series of coral reefs enclosing vast clear lagoons sometimes many miles across. The reefs once encircled volcanoes which have long since sunk back into the sea leaving these long narrow curving islands covered in coconut palms. There is usually less than 50 metres (55 yards) between the lagoon and the Pacific. This is Majuro Atoll, a 47km (29 mile) long strip of land. It contains the county's main airport and in this section its capital, Majuro. Built at the atoll's widest point which is less than half a kilometre (1/3 mile) across. 2004.