What is Lexington and Concord and why was it important?

Lexington and Concord were two small towns not far to the northwest of Boston at the time of the Revolutionary War.  There were small battles in each of these towns on April 19, 1775.  These battles were important because they were the first battles of what we now know as the Revolutionary War.

In 1775, the British Army leaders in Boston had heard that the Patriots were storing weapons and gunpowder in Concord.  They had also heard that some Patriot leaders were in Lexington.  They decided to make a foray out to capture the leaders and the gunpowder.  At this time, tensions were clearly high between the British and the colonists, but no military fighting had yet occurred.  When the British Army went to Lexington and Concord, this changed.  Battles were fought at the two towns and the British were harried by American militia members as they returned to Boston.  This fighting is important because it is generally seen as the beginning of the Revolutionary War.