<Li> At U.S. Customs and Border Protection Ports of Entry that are continuously open . </Li> <Li> A Civil War era flag (for the year 1863) flies above Pennsylvania Hall (Old Dorm) at Gettysburg College . This building, occupied by both sides at various points of the Battle of Gettysburg, served as a lookout and battlefield hospital . </Li> <Li> Grounds of the National Memorial Arch in Valley Forge NHP, Valley Forge, Pennsylvania </Li> <Li> By custom, at the Maryland home, birthplace, and grave of Francis Scott Key; at the Worcester, Massachusetts war memorial; at the plaza in Taos, New Mexico (since 1861); at the United States Capitol (since 1918); and at Mount Moriah Cemetery in Deadwood, South Dakota . </Li>

What do the 7 stripes on american flag represent