The first Allied and Royal Australian Navy submarine lost in World War I has finally been found after a 103-year search off the coast of Papua New Guinea.
"Australia's oldest naval mystery has been solved," said Australian Defence Minister Marise Payne.
"It was a significant tragedy felt by our nation and our allies."
The HMAS AE1 was holding 35 crew members when it went missing off the coast of the Duke of York Islands in September 1914.
Twelve previous private and government-funded expeditions over the years failed to find the vessel, which was a grave to so many.
The latest, 13th and final search began on board the vessel Furgro Equato last week.
The missing sub was found yesterday 300 metres under water.
After the discovery, the crew on board the Furgro Equato took part in a commemorative service to remember the officers and sailors who lost their lives.
"The boat and her crew, who've been on eternal patrol since 1914 … have now been found," Ms Payne said.
"I truly trust that this discovery will bring peace of mind to the decedents of the families of the crew who lost their lives on board and perhaps in time it may also enable us to discover what caused the submarine to sink."
Ms Payne said the Australian Government would work with the Papua New Guinea Government to preserve the underwater site and to form a plan for a lasting commemoration.
The search party was jointly funded by the Australian Government, the Silentworld Foundation, The Australian National Maritime Museum and Find AE1 Ltd.