Our 4th Park in our 4th State was Jefferson National Expansion Memorial   http://www.nps.gov/jeff/index.htm   Or better know as St. Louis' Gateway Arch!  This is a major tourist attraction and was loaded with vacationers.  We had been here before, the temperature was 102, we ran in got our stamp and ran out.  

The National Parks Visitor Center is at the base of north end of the arch.  The reason for the name and this park is this is a memorial to Thomas Jefferson's role in the opening of the West!!  Definitely a distination trip!!  Enjoy....