Bikini Atoll (/ˈbɪkɪˌniː/ or /bɪˈkiːni/; Marshallese: 'Pikinni', [pʲi͡ɯɡɯ͡inʲːii̯], meaning "coconut place") is an atoll in the Marshall Islands that was the site of 23 nuclear tests during the 1940s and 1950s. The atoll consists of 23 islands totalling 3. 4 square miles (8. 8 km2) surrounding a 229. 4-square-mile (594. 1 km2) central lagoon. It is at the northern end of the Ralik Chain, approximately 87 kilometres (54 mi) northwest of Ailinginae Atoll and 850 kilometres (530 mi) northwest of Majuro. Within Bikini Atoll, Bikini, Eneu, Namu and Enidrik islands comprise just over 70% of the land area. Bikini and Eneu are the only islands of the atoll that hosted a permanent population. Bikini Island is the northeastern most and largest islet. The atoll was also known as Eschscholtz Atoll, after German naturalist Johann Friedrich von Eschscholtz, until 1946, after the Marshall Islands were captured by the U. S. during World War II.