In Holland, the graves of Allied casualties from WW2 are often 'adopted' by local folk, who ensure that flowers are regularly placed on the 'their' grave. In particular, this is done on significant anniversaries (Liberation Day/US Memorial Day etc.)
I was at Margraten (east of Maastricht) US Cemetery a few years ago on Liberation Day (May 05). The place was a sea of flowers, placed by local Dutch folk, who were there in large numbers. General David Petraeus (US Army) was there & I managed a few words with him as his entourage passed by. He was amazed & clearly moved by this display by the Dutch people.
Based as I am in north-central Europe, I always endeavour to visit as many of these places as possible on my travels.
Lest we forget........
HB