Gateway Arch is the smallest National Park in the NPS System, at just under 4 million square feet.  But it packs a mighty historical punch in that it commemorates the Louisiana Purchase and subsequent westward movement of American pioneers and settlers west of the Mississippi. Old Courthouse, directly behind the Arch, was the site of the famous case where enslaved Dred Scott fought for his freedom through the courts system, and Virginia Minor fought for the Women's Right to Vote.