The world's last male northern white rhino has died in Kenya, aged 45.
The death of the rhino named Sudan leaves behind only two surviving females of the subspecies, which has been sent into gradual decline by ongoing poaching.
Its horn is considered valuable in parts of Asia due to beliefs it can cure illnesses.
Sudan's health had gradually deteriorated and he was being treated for infections and age related issues.
He spent his final days surrounded by armed guards in the Ol Pejeta Conservancy, a not-for-profit conservation area for threatened animals.
Ol Pejeta representative Elodie Sempere told CNN that Sudan was a "gentle giant".
"His personality was just amazing and given his size, a lot of people were afraid of him. But there was nothing mean about him," Ms Sempere said.
The Ol Pejeta Conservancy is now hoping the rhino's genetic information can be used for artificial insemination.
WildAid CEO Peter Knights told CNN he hopes the world can learn from the sad loss of Sudan and take every measure to end all trade in rhino horn.
"While prices of rhino horn are falling in China and Vietnam, poaching for horn still threatens all rhino species," Mr Knight said.
WildAid is an American environmental organisation which aims to reduce demand for wildlife products.