French President Francois Hollande hosted his German counterpart, Joachim Gauck, on Sunday morning to commemorate the 100th anniversary of the day Germany declared war on France, reports Deutsche Welle.
The centenary ceremony began with both leaders laying a wreath in Hartmannswillerkopf, one of only four official national memorials dedicated to the First World War in France.
The two presidents were then to lay the first stone of a World War One museum.
Alsace carries special historical significance as land naturally divided on its eastern border with Germany by a long stretch of the Rhine River, but pulled in both directions over the centuries by war.
Hartmannswillerkopf lies roughly 50 kilometers (30 miles) from the German border and was considered a key strategic site for securing the surrounding area. Over 30,000 soldiers lost their lives on its battlefield, which changed sides eight times during the war.
Both leaders spoke of the challenges facing modern Europe, including difficult economic decisions and heated political debates calling into question the need for the European Union. The threat of a full-scale war in Ukraine has also worried neighboring EU countries.
"We no longer have eyewitnesses to the First World War" French President Hollande said. "It is up to us to recall these barbaric events."
Citing the symbolic importance of modern Franco-German relations compared to the years of mutual enmity that led to heavy losses of life, Hollande said Sunday's event was "a message to the world and an invitation to all those all over the world [wherever confrontations arise.]"
"Peace is the responsibility of every single generation...and to transmit to coming generations the fragility of peace."
Hollande noted that these lessons must help guide European leaders in their diplomacy toward countries at war, including in the Middle East and Africa.
Echoing his French counterpart, German President Gauck remarked on the significance of having French and German citizens sit alongside one another in peace.
"It is like a dream, but it is our reality," Gauck said.
Read more of this report from Deutsche Welle.