Today is a day of reflection for many. As a nation we're still conflicted about what 9-11 meant—and means. Some view it as an inevitable Clash of Civilizations, others as a tragic and unforeseen consequence of decades of political decisions. Inevitably an event so overwhelming leaves a number of questions in its wake. The best thing we can do ten years later is try to understand why and how such an event could occur. And today, of all days, we simply need to remember. Here are photos of 9-11 remembrances across the nation. And you can see video of the anniversary ceremonies here.