This is an annual cross-state ride called RAGBRAI. It's been going for 52 years now. Riders typically use support teams, but I ride self-supported from the center of the state, ride half the route, and ride home. More photos:
I'm trying to imagine what flat midwest/central USA would look like to the naked eye if air didn't obscure sightlines. Like if the air were absolutely perfectly infinitely clear, no fog, no mist, etc. Like if it were a game and you set the view distance to infinite.