Russian President Vladimir Putin will lead tributes to mark the 70th anniversary of the end of the Battle of Stalingrad.
The city of Stalingrad, which was renamed Volgograd in 1961, will regain its wartime name for the event, following a council decision.
Around one million people are thought to have died in the battle, as Soviet troops defeated the Germans.
It is considered one of the major turning points of World War II.
The vast death toll is not the only reason why the battle has huge significance in Russia, the BBC’s Moscow correspondent Daniel Sandford reports.
It is seen as the moment when the tide was turned against the Nazis.
From Stalingrad some Soviet soldiers fought all the way to Berlin, he adds.
The defeat threw Hitler’s offensive in the Soviet Union into disarray.
The victory in World War II is one of the things that unites all Russians, our correspondent adds.
‘Hero city’
President Putin will lead the solemn commemorations at the battle site, which will include a military parade and a wreath-laying ceremony at the eternal flame in the Hall of Heroes.
There will also be an 18-gun salute with World War II-era Soviet artillery.
“At the heart of all Russia’s victories and achievements are patriotism, faith and strength of spirit,” Mr Putin said in a televised speech on Friday.
“In Word War II, these true values inspired our people and our army.”
Some German veterans have also been invited to the tribute, along with senior military commanders from Russia’s allies in the war – Britain and the US.
On Wednesday, the council of Volgograd passed a decision to restore the city’s wartime name of Stalingrad on six specific days a year.
The dates, all associated with military commemorations, are 2 February, 9 May, 22 June, 23 August, 2 September and 19 November.
Under the decision, the title “Hero City Stalingrad” will be used during commemorations as “a symbol of Volgograd”, the council said.
“We may use this symbol officially in our speeches, reports and while conducting public events,” the council ruling states.
The decision was taken after “numerous requests” from World War II veterans, officials said.
The city has had three names during the past century. It was originally known as Tsaritsyn before being renamed in 1925 in honour of Soviet leader Joseph Stalin, who led Bolshevik forces there during the Russian Civil War.
The German attack on Stalingrad began on 19 August 1942.
Stalingrad was a strategically important city in their campaign to occupy the south of Russia and take control of the Caucasus oilfields.
It was also of symbolic importance because of its name.
After six months of ferocious fighting, Soviets troops eventually smashed the German siege.
It is one of the bloodiest battles in modern history.