Could this be an early example of an environmentally friendly green roof -- or just a serene spot to picnic above the din of downtown traffic? Either way, it's long gone. The Thrivent Financial building and parking lot now fill the block. In the background of this photo you can see the Northwestern Bell (now CenturyLink) building; at right is City Hall. Behind the mower was Andrew W. Carlson, 815 E. Lake St. Do you recognize him -- or have any memories of the Treasure Masters building? The company, formerly Package Masters, expanded the building in 1945. The Minneapolis company designed, manufactured and distribute "internationally hand painted greeting cards, gift packets for handkerchiefs and hosiery and allied items," according to a Tribune story on the expansion plans.