Reefs are generally divided into three categories; the barrier reef, the atoll , and the fringing reef.
The main island, the Tarawa atoll , is only a few metres above sea level and houses around 40,000 people.
The northern islands are coral atolls that have formed over ancient sunken volcanoes and are characterized by outer reefs surrounding a lagoon.
Diving is generally within the atoll lagoons for the inexperienced, and outside the atolls on reef walls for the advanced.
On outer islands and atolls , however, most matters are settled internally, with little reliance on the state judicial apparatus.
The Marshall Islands are a group of low-lying coral atolls and islands in the central Pacific Ocean.
Banaba is a raised limestone island, but the other islands are all coral atolls , and most have lagoons.
The Maldives include nearly 1,200 islands in 15 major atolls spanning approximately 470 miles to just south of the equator.
Hidden beneath the salty Pacific, the coral atolls along the northwestern Hawaiian chain put an abrupt end to many a daring seafarer's adventure.
The tsunami swamped up to 40 percent of the Maldives, an Indian Ocean string of 1,192 coral atolls 480 km southwest of the southern tip of India.