The flags of three nations flew above the Mississippi River Sunday.

Thousands gathered at the Gateway Arch in St. Louis to mark 200 years since the United States took control of the Louisiana Terrority from France.

The 1804 treaty was a pivotal moment in the histories of the United States, Spain, France, and also for countless American Indian Nations. KWMU's Kevin Lavery prepared this report on the legacy of the Louisiana Purchase. © Copyright 2010, St. Louis Public Radio