A special memorial has been unveiled to remember hundreds of East Midlands soldiers who died on a World War I battlefield in France in October 1915.
French and British groups supported the memorial campaign
The men were killed at a site known as the Hoenzollern Redoubt which had remained unmarked for decades.
Lincoln architect Michael Credland designed the memorial after discovering the site was earmarked for a dump.
Hundreds of relatives from the East Midlands attended a ceremony at the French battlefield in Loos.
"It was the East Midlands' black day - with enormous casualties from towns and villages across the region," Mr Credland said.
"They are still finding bodies of both Germans and British - it upset us a great deal. It was a memorial and a grave."
An 18-month fight, backed by local French enthusiasts, meant the dumping was finally stopped.
Mr Credland's great uncle, Regimental Sgt Major Frank Credland, survived the battle at Loos - which was a fortified series of German trenches that stuck out towards the Allied line.
The soldiers who died were mostly from the 46th North Midlands Division and hailed from Nottinghamshire, Staffordshire, Lincolnshire, Leicestershire and Derbyshire.
The memorial was designed by the great nephew of a veteran
"They were immediately cut down by machine guns in the no-man's land and 3,000 men were dead or wounded within half an hour," historian Martin Middlebrook said.
"It was a useless waste of infantry."
Richard Lane of the Royal Leicestershire Regiment said: "It was a terrible day for Leicester city - I don't think historically we have ever lost so many people."
Pupils from Gainsborough's Middlefield School of Technology travelled to the unveiling in Loos.
The entire Loos offensive in autumn 1915 resulted in 50,000 British casualties.
The memorial is made of white Portland stone with an octagon design showing a broken column.