1-3 July marks the 150th anniversary of Gettysburg, the battle that many historians cite as a key turning point in the US civil war, which left nearly 50,000 Union and Confederate soldiers dead, wounded or captured on Pennsylvania farmland. In 1913, on the 50th anniversary of the battle, the same fields played host to the largest ever gathering of civil war veterans, where former soldiers from both sides – many in their 70s – returned to commemorate the war