Summary: In a solemn commemoration of Memorial Day, President Barack Obama participated in a wreath-laying ceremony at the Tomb of the Unknowns at Arlington National Cemetery near Washington, D.C. … One-year retrospective: One year ago today, on May 30, 2010, Aubrey Immelman reported that Chinese Premier Wen Jiabao expressed no support for proposed U.N. sanctions against ally North Korea over its alleged sinking of the South Korean warship Cheonan, declining to join other key nations in blaming Pyongyang.