Lots of double letters...
"The Mississippi River is the largest river system in North America.[3][4] About 2,320 miles (3,730 km) long,[5] the river originates at Lake Itasca, Minnesota and flows slowly southwards in sweeping meanders, terminating 95 river miles belowNew Orleans, Louisiana where it begins to flow to the Gulf of Mexico. Along with its major tributary, the Missouri River, the river drains all or parts of 31 U.S. states stretching from the Rocky Mountains in the west to the Appalachian Mountains in the east to the Canada-U.S. border on the north, including most of the Great Plains, and is the fourth longest river in the world and the tenth most powerful river in the world."
http://www.delcampe.com/page/item/id,0037980005,language,E.html
Here's another version of a maximum card with this stamp - notice the BEFORE and AFTER shape:
