A Tulsa landmark is celebrating 100 years of operation,

When PSO's Tulsa Power Station along the Arkansas River first opened, it was a coal-powered plant run by Oklahoma Power Company. The iconic 336-foot sign wasn't added until a few years later, when the ownership changed.

"In 1927, when PSO bought the plant, they put the first version of the sign there. That's just a visionary thing. I think Tulsa had a reputation as an electric light city. Well, that's how we prove it every night. We light up the night with that sign." said Wayne Greene from PSO.

The plant still operates 24 hours a day, but was converted to natural gas after world war two.