1775: An expedition of 700 British regulars under the command of Lt. Col. Frances Smith departs Boston to seize and destroy military stores of the Massachusetts Militia in Concord. At dawn, 70 militia members led by Capt. John Parker meet the British at Lexington, and the two sides briefly skirmish. The Americans withdraw and regroup, attacking the redcoats again at North Bridge with a much larger force, forcing the British to turn back towards Boston. The American Revolution has begun. 1861: 86 years to the day after the “shot heard round the world,” Massachusetts volunteers headed for Washington, D.C. are...