There are more of these markers around town.

From the Voyager Facebook Page: "The Voyage exhibition was permanently installed in Kansas City, Missouri, on October 10, 2008. The exhibition is located along Baltimore Avenue, from the Power & Light Building to historic Union Station. Voyage provides an experiential thread along a 1 mile path through downtown Kansas City. Voyage is provided as a gift to Kansas City by the Ewing Marion Kauffman Foundation, which also commissioned two new stanchions for the dwarf planet Eris and one dedicated to the Explorers among us." Also see http://www.bloomandgrowforever.com/scale-solar-system-model/

Photo was taken at dusk with a Cell Phone. Nevertheless in the full sized image, you can clearly read the writing and directions to Eris.