Only near the southern end of this natural coral barricade do two open passages permit safe ship navigation from one side of the Indian Ocean to the other through the territorial waters of Maldives. For administrative purposes, the Maldivian government organised these atolls into 21 administrative divisions. The largest island of Maldives is that of Gan, which belongs to Laamu Atoll or Hahdhummathi Maldives. In Addu Atoll, the westernmost islands are connected by roads over the reef (collectively called Link Road) and the total length of the road is .