Today is 𝗩𝗼𝗹𝗸𝘀𝘁𝗿𝗮𝘂𝗲𝗿𝘁𝗮𝗴 in Germany. It (now) takes place on the second Sunday before the first Advent Sunday and commemorates all victims of war and violence.
It is often „celebrated“ or observed on the national stage as well as in the communities. Like the photo of Ehrenhain shows, wreaths are laid down at cemeteries at the war graves. Though nowadays we don‘t only think of the fallen soldiers of the two World Wars but all victims who died during the wars and acts of violence.
𝗩𝗼𝗹𝗸𝘀𝘁𝗿𝗮𝘂𝗲𝗿𝘁𝗮𝗴 or National Day of Mourning started after World War to commemorate the fallen of WWI. In the 1920s it took place in March on various different days. It was also used by the political parties to further their own agenda.
In West Germany in 1952, the 𝗩𝗼𝗹𝗸𝘀𝘁𝗿𝗮𝘂𝗲𝗿𝘁𝗮𝗴 was set on the second Sunday before Advent, and that‘s still when it is.
The closest equivalent to a US holiday is Memorial Day the end of May. However, Memorial Day commemorates only fallen service members and doesn‘t include other victims of war and violence like the German 𝗩𝗼𝗹𝗸𝘀𝘁𝗿𝗮𝘂𝗲𝗿𝘁𝗮𝗴 now does.
And unlike Memorial Day with its parades, picnics, and sales, Germany‘s National Day of Mourning has a religious component and is a „quiet day“ which means the day should be spent in quiet and contemplation. Music and dance events are forbidden.