Commemorations will be held this summer to mark the huge of loss of life caused when a Royal Navy battleship was blown apart at Scapa Flow in Orkney.
More than 800 died when a series of internal explosions destroyed HMS Vanguard on the night of 9 July 1917.
It is considered to be one of the most tragic accidents in the history of the Royal Navy.
A musical concert and a service of commemoration are among events planned to mark the sombre centenary.
The dreadnought battleship, which saw action at the Battle of Jutland, was anchored in Scapa Flow when it was destroyed by onboard explosions.
Just three of the 845 men on board were recovered alive and one later died of his injuries.
The wreck now lies in 14m of water, to the north of the island of Flotta. It has statutory protection as a designated war grave.
Relatives of some of those who died will be among those taking part in a series of commemorative events on 9 July.
The events include:
- A concert in St Magnus Cathedral, Kirkwall, on 8 July, performed by an ensemble and Corps of Drums from the band of HM Royal Marines
- Two modern Royal Navy vessels will take part in a wreath-laying service above the wreck of the Vanguard on 9 July
- A service of commemoration at the Lyness Royal Naval Cemetery in Hoy, where 41 of the ship’s crew were buried
- A watch night service at St Magnus Cathedral will mark the moment when the ship went down at 23:20
“These will be very poignant events,” said Brian Archibald, of Orkney Islands Council.
“They offer the opportunity to remember the sinking of HMS Vanguard and the terrible loss of life in Scapa Flow on that July day 100 years ago.
“We are very pleased that descendants of men who served aboard the ship will take part in the commemorations.
“There will be limited space aboard the vessels involved in the laying of wreaths above the wreck, and so priority will be given to relatives who have travelled to Orkney for the occasion.
“Many other people from our community will want to play their part in commemorating the loss of the Vanguard and her crew, and all are welcome at the services at Lyness Cemetery and back in the cathedral on 9 July.”