I use to eat at Harry's often about 20 years ago. He didn't trust any of his employees. He always ran the register, no one was allowed to touch it.
the other character on that block was Perry and Perry's deli. One of the best delis in the city. It still exists but it's a shadow of what it once was, it shares space with the Bacci pizza along Franklin on that same block.
I started working at 333 W Wacker in late 2000, I remember walking past the old Merc building as they were tearing it down, not aware of what is was. Never ventured inside, wish I had.