And an acclaimed marathon swimmer from the United States has taken more than four hours to complete an eight mile swim from Aunuu island to Utulei Beach in American Samoa.
Bruckner Chase made the swim as part of a nationwide campaign by national marine sanctuaries to promote ocean awareness.
Students from Samoana High School rowed their long boat alongside Chase and marine patrol cops followed the swimmer the whole distance.
He says conditions certainly made the swim challenging.
"Just very hot. The waves and the surf after we got clear of Aunuu was - the waves were big. It was choppy, it was very hard - the heat and the hot water was brutal. My calves were cramping up and it was because of all of you that this was possible. I cannot do any of this by myself. I need communities to do more and I have never met a community like I have in American Samoa."