VERDUN, France (AP) -- In solemn ceremonies Sunday in the forests of eastern France, French President Francois Hollande and German Chancellor Angela Merkel marked 100 years since the Battle of Verdun, determined to show that, despite the bloodbath of World War I, their countries' improbable friendship is now a source of hope for today's fractured Europe.
The 10-month battle at Verdun — the longest in World War I — killed 163,000 French and 143,000 German soldiers and wounded hundreds of thousands of others.
Between February and December 1916, an estimated 60 million shells were fired in the battle. One out of four didn't explode. The front line villages destroyed in the fighting were never rebuilt. The battlefield zone still holds millions of unexploded shells, making the area so dangerous that housing and farming are still forbidden.
With no survivors left to remember, Sunday's commemorations were focused on educating youth about the horrors and consequences of the war. Some 4,000 French and German children were taking part in the day's events, which conclude at a mass grave where, in 1984, then-French President Francois Mitterrand took then-German Chancellor Helmut Kohl's hand in a breakthrough moment of friendship and trust by longtime enemy nations.
"Verdun is the more than the name of your town — Verdun is also one of the most terrible battles humanity has experienced," Merkel said in a speech at city hall, calling Hollande's invitation to join the centenary "a great honor."
"We are all called upon to keep awake the memory (of Verdun) in the future, because only those who know the past can draw lessons from it," the German leader said.
Hollande praised the city of Verdun as "the capital of peace."
"Verdun is a city that represents — at the same time — the worst, where Europe got lost, and the best, a city being able to commit and unite for peace and French-German friendship," he said.
Merkel said the commemorations show "how good relations between Germany and France are today" and the achievements of European unity.
"In a world with global challenges, it is important to keep developing this Europe," she said in a weekly address Saturday, expressing hope that Britain would not vote to leave the European Union in a June 23 referendum.
Amid rising support for far right parties and divisions among European countries over how to handle refugees, Hollande said he wants to work alongside Merkel to "relaunch the European ideal."
"We must take action ... at a moment when Europe is affected by the disease of populism," he told France Culture radio this week. He also noted the threat from violent extremism, saying the EU "must protect the people," especially against "terrorism."
Hollande and Merkel spent the entire day together. In the morning, he welcomed his German counterpart under heavy rain at the German cemetery of Consenvoye, near Verdun, where 11,148 German soldiers are buried. They laid a wreath, accompanied by four German and French children, and walked side by side for few minutes in the cemetery, sharing an umbrella.
After lunch, they were visiting the newly renovated Verdun Memorial. The museum, which reopened in February, immerses visitors in the "hell of Verdun" through soldiers' belongings, documents and photos, and from its new rooftop, they can observe the battlefield.
"The visit follows the steps of the soldiers. First reaching the front, moving into shell holes, fighting, surviving on the front line, the daily life," said historian Antoine Prost.
Verdun has become a common place of remembrance because "it's a place of massive death equivalent for the French and the Germans," Prost added.
The main ceremony will take place in the afternoon at the Douaumont Ossuary, a memorial to 130,000 unidentified French and German soldiers. The ceremony conceived by German filmmaker Volker Schloendorff will include children re-enacting battlefield scenes to the sound of drums amid thousands of white crosses marking the graves.