The Maldives are formed of 26 atolls, or atholhu in Dhivehi — the source of the English word. These are not single islands, but giant ringlike coral formations hundreds of kilometres wide that have fragmented into countless islands.
Atoll naming is complex, as the atolls have both lengthy traditional Dhivehi names like Maalhosmadulu Dhekunuburi, and snappy code names like Baa that refer to administrative regions and may consist of more than one geographical atoll. The code names are actually just the letters of Dhivehi alphabet, but being easier for non-Maldivians to remember and pronounce, the code names are popular in the travel industry and are hence also used here. Of the 20 administrative atoll groups, only (parts of) 10 are open to tourism, and from north to south these are: