The Museum of the American Revolution in Philadelphia has announced it will open on April 19 next year. It's the anniversary of the opening battles in 1775 between British troops and American colonists in Lexington and Concord and the "shot heard round the world."

One of the marquee exhibits will be Gen. George Washington's headquarters tent during the Valley Forge winter of 1777-78. It will be viewable through a glass wall and in a completely sealed environment.

The museum has built up a large collection, including guns and other artifacts from the first fighting of the Revolutionary War.

Officials say they were able to set an opening date after philanthropist H.F. "Gerry" Lenfest gave the museum a $10 million donation on top of his previous $40 million matching gift.