Divers get close-up looks of marine animals in the Marine Life Park of Singapore's Resorts World Sentosa (RWS), May 21, 2013. RWS Marine Life Park debuts its Open Ocean Dive which offers certified divers the opportunity to get close with marine animals. (Xinhua/Then Chih Wey)

Two manta rays swim in the Marine Life Park of Singapore's Resorts World Sentosa (RWS), May 21, 2013. RWS Marine Life Park debuts its Open Ocean Dive which offers certified divers the opportunity to get close with marine animals. (Xinhua/Then Chih Wey)

Divers get close-up looks of marine animals in the Marine Life Park of Singapore's Resorts World Sentosa (RWS), May 21, 2013. RWS Marine Life Park debuts its Open Ocean Dive which offers certified divers the opportunity to get close with marine animals. (Xinhua/Then Chih Wey)

Divers get close-up looks of marine animals in the Marine Life Park of Singapore's Resorts World Sentosa (RWS), May 21, 2013. RWS Marine Life Park debuts its Open Ocean Dive which offers certified divers the opportunity to get close with marine animals. (Xinhua/Then Chih Wey)

Divers get close-up looks of marine animals in the Marine Life Park of Singapore's Resorts World Sentosa (RWS), May 21, 2013. RWS Marine Life Park debuts its Open Ocean Dive which offers certified divers the opportunity to get close with marine animals. (Xinhua/Then Chih Wey)

A man takes pictures of the divers diving with marine animals in the Marine Life Park of Singapore's Resorts World Sentosa (RWS), May 21, 2013. RWS Marine Life Park debuts its Open Ocean Dive which offers certified divers the opportunity to get close with marine animals. (Xinhua/Then Chih Wey)

Divers get close-up looks of marine animals in the Marine Life Park of Singapore's Resorts World Sentosa (RWS), May 21, 2013. RWS Marine Life Park debuts its Open Ocean Dive which offers certified divers the opportunity to get close with marine animals. (Xinhua/Then Chih Wey)