The centenary of the most deadly explosion on British soil during World War One is being marked be a series of events.
The blast tore through the Chilwell munitions depot on 1 July 1918 and resulted in the deaths of 139 people.
The Nottinghamshire depot - one of the largest in the country - employed about 6,000 people and produced 1,260,000 shells in its first year.
Most bodies could not be identified and were buried in a mass grave.
The Chilwell site was one of several large factories set up in 1915 and 1916 to feed the guns of the Western Front, and because many men were away fighting they were mainly staffed by women.
About eight tonnes of TNT exploded at the depot, with windows broken a mile away and a column of smoke visible across much of the county as a result.
The blast was heard 20 miles away, but all but 12 of the surviving employees returned the next day for work.
Four years ago a BBC documentary found footage of workers at the factory in a garden shed in Beeston.
Rebecca Harding of the Imperial War Museum said the footage was particularly important: "It is quite different to most war time propaganda.
"It is a lot more natural, organic, almost fly-on-the-wall documentary style, without that deliberate message you usually get in propaganda."
Last year a local church group teamed up with Royal Engineers to replace a lost wooden cross with a metal one in time for the tragedy's centenary.
A special commemorative mass is to be held at St Mary's Church in Attenborough to mark the centenary, with the new memorial being unveiled.
Rev Jonathan Smithurst said the new memorial is a "simple but dignified" way of remembering the tragedy.
The service will include the Nottinghamshire Band of the Royal Engineers and a two minute silence at 19:10, the time of the explosion.
Earlier in the week there were public screenings of the restored footage, a play performed by children at Chetwynd Barracks in a hangar close to the site of the blast and a period tea party at St Mary's.
Follow BBC East Midlands on Facebook, on Twitter, or on Instagram. Send your story ideas to firstname.lastname@example.org.