The Okinawa Churaumi Aquarium (沖縄美ら海水族館 Okinawa Churaumi Suizokukan) is located within the Ocean Expo Park in Okinawa, Japan. It welcomed its 20 millionth visitor on 30 March 2010 and is a member of the Japanese Association of Zoos and Aquariums (JAZA). It was the largest aquarium in the world until it was surpassed by the Georgia Aquarium in 2005. The aquarium has the theme of “Encounter the Okinawan Sea”. In 1975, the World’s Exposition or World’s Fair was held in Okinawa, Japan at the Ocean Expo Park. Afterward, the park began to lose tourism and it was believed that a new aquarium would help revive the area and celebrate Okinawa’s marine tradition. The aquarium was designed by Yukifusa Kokuba and was opened on 1 November 2002. “Churaumi” was selected as the name of the aquarium by public vote amongst Japanese people. “Chura” means “beautiful” or “graceful” in the Okinawan language, and “umi” means “ocean” in Japanese.The public aquarium is a part of the Ocean Expo Park located in Motobu, Okinawa. The aquarium is made up of four floors, with tanks containing deep sea creatures, sharks, coral and tropical fish. The aquarium is set on 19,000 m2 of land, with a total of 77 tanks containing 10,000 m3 of water. Water for the saltwater exhibits is pumped into the aquarium from a source 350 m offshore, 24 hours a day. The main tank, called the Kuroshio Sea, is 35 metres (115 ft) long, 27 metres (89 ft) wide and 10 metres (33 ft) deep. It holds 7,500,000 litres (1,981,000 US gal) of water and features an acrylic glass panel measuring 8.2 by 22.5 metres (27 by 74 ft) with a thickness of 60 centimetres (2 ft),the largest such panel in the world when the aquarium was opened. Whale sharks and manta rays are kept alongside many other fish species in the main tank. The world’s first birth of a manta ray in captivity was at the aquarium in 2007 and involved the reef manta ray (this species and the giant oceanic manta ray were only recognized as separate species in 2009, meaning that all were listed as Manta birostris until then). As of July 2010, there have been a total of four reef manta rays born in the aquarium. Since 2018 they also keep giant oceanic manta ray. The first attempt of keeping whale sharks in an aquarium was initiated in 1980 by the Ocean Expo Park (the predecessor of Okinawa Churaumi Aquarium) and it remains one of the few aquariums that maintain the species. Most were obtained from incidental catches in coastal nets set by fishers (none after 2009), but two were strandings. Several of these were already weak from the capture/stranding and some were released, but initial survival rates were low. After the initial difficulties in maintaining the species had been resolved, some have survived long-term in captivity. The record for a whale shark in captivity is an individual that, as of 2017, has lived for more than 18 years in the Okinawa Churaumi Aquarium. Okinawa Churaumi is trying to breed whale sharks in captivity, which has never been achieved by an aquarium. Their oldest male reached sexual maturity around 2012 and began to show an interest in females in 2014. The current female on display (another is maintained offshow) is 8 m (26 ft) long and expected to reach sexual maturity when 9 m (30 ft). The aquarium holds 80 species of coral. Their corals have spawned every year at the aquarium since 2001.