The Interstate 80 bridge over the Mississippi River between Iowa and Illinois can be seen Monday, April 12, 2021, in Le Claire, Iowa. Chad Pregracke, an environmentalist whose Living Lands & Water operation has been cleaning up the Mississippi River for years, has a plan for the existing bridge if a new bridge is constructed to replace it elsewhere over the river. The Bison Bridge would take the current bridge connecting Iowa to Illinois, which is scheduled to be replaced, and transform it into grazing habitat for bison with 50 acres in each state. (Erin Hooley / Chicago Tribune)