LITTLE BIGHORN BATTLEFIELD NATIONAL MONUMENT, Mont. — The quiet, wind-swept hills of the Battle of Greasy Grass, known to many as the Battle of Little Bighorn, are the setting for Native Americans commemorating the battle’s 150th anniversary with horse rides, battle reenactments and a camp of hundreds of people this week. The battle, one of the most famous and symbolically charged events in American history, marked its anniversary Thursday.