Tiny treasures around every corner. Oldest building in #chicago Crain's said "The tiny building in an alley at 22 E. Jackson Blvd. is believed to be the oldest standing structure in the Loop. Official city records say the building known as the Pickwick Stable was completed in 1892. But according to the Chicago Tribune which traces its ownership to Henry Horner grandfather of an Illinois governor by the same name there was a stable at this location as early as 1857."