Atoll of an atoll is very small in comparison to the total area. Atoll islands are low lying, with their elevations less than 5 meters (9). Measured by total area, Lifou (1146 km²) is the largest raised coral atoll of the world, followed by Rennell Island (660 km²). More sources however list as the largest atoll in the world in terms of land area Kiritimati, which is also a raised coral atoll (321.37 km² land area; according to other sources even 575 km²), 160 km² main lagoon, 168 km² other lagoons (according to other sources 319 km² total lagoon size). The
Baa Atoll Biosphere Reserve the environment. Baa Atoll has a warm and humid tropical climate. The weather is dominated by two monsoon periods – a rainy monsoon period, which lasts from May to November, and a dry monsoon period, which lasts from January to March. The dominant natural environment of the reserve is marine, surrounded by deep ocean. The water depth varies considerably and includes lagoons with depths ranging from 30 m to 80 m, opening into the Indian Ocean, while channels running through the atoll may be up to 250-300 m in depth. The lagoons enclose a variety of reef structures including faros,