On the edge of the former American parade grounds, this delightful museum details the history of Clark from 1901 up to its development of the Freeport Zone. It includes some great military memorabilia, photos and displays on Mt Pinatubo's dramatic eruption (perhaps best seen after you've climbed it!). There's also interesting info on the indigenous Aeta, the earliest inhabitants of the area who still live in the region.
While you're here take a stroll around the peaceful Parade Grounds , ringed by historic Barn houses built in the early 20th century that served as former residences of US soldiers.