Diamonds are a girl's best friend. When it was built, Mills Tower guarded the crossing of the Rock Island and the Illinois Central. Long since closed, the tower now stands watch as the Union Pacific Spine Line (ex-RI) and Canadian National (ex-IC) cross. On September 25, UP Challenger 3985 bounced across the diamond on its way to the Twin Cities. Note the two signs at right, one for each railroad, marking this location as Mills.