Tonga (full name, Kingdom of Tonga) is an archipelago in the South Pacific Ocean, between Hawaii and New Zealand. With an area of approximately 750 sq km and 419 km of coastline, most of Tonga’s islands have a limestone base. The country is divided into three island groups: Ha'apai, Tongatapu and Vava'u. Nuku'alofa is the capital, with a time difference of 13 hours ahead of GMT. The currency is the pa'anga, and exports include fish, pumpkins, coconut products and vanilla beans. The population of approximately 121,000 people comprises an ethnic mix of Polynesian and Europeans. The primary languages are Tongan and English, and the predominant religion is Christianity.