We tend to celebrate something on most holidays. New Year’s Day brings revelry the night before. July Fourth has us in backyards, standing by the barbecue and watching the fireworks. Thanksgiving and the winter holidays — Christmas and Hanukkah — bring us near friends and family, celebrating and thankful for what we have. And then there’s Memorial Day, a different kind of holiday. It’s not that the day is bereft of any celebration. People will always gather during a three-day weekend, taking advantage of an extra day off and, when it’s in late May, the beautiful weather. But this holiday is more than merely the unofficial start of summer. It’s a solemn remembrance of those who have died in service of our country. It’s a day when many people will visit cemeteries, place a flag at the headstone and stand, silently, just for a moment, to remember.