The most popular pizza chain to come out of St. Louis originated in the Tower Grove area in 1964. Started by Ed & Margie Imo, Ed worked as a tile cutter/setter by the day. On Friday nights, the Imos would wait until 11:30 at night to order pizza (for religious purposes) from restaurants at the Hill neighborhood. Then there was that one night a great idea struck upon the couple: why not have a pizza parlor deliver it to them?
The Imos decided to open a pizza place on Thurman Street, and the rest is history. Their first cash register was a fishing tackle box. Since the store was small, it was not a dine-in, but rather a carry-out/delivery place. Some sources point this to be the first pizza restaurant to do such thing (call-in, carry-out), but there is no real evidence or proof. Nonetheless, they have prospered into one of the most successful restaurants to come out of St. Louis. Imo's became a franchising company in 1985. As of this writing, I do not have the date of when the original location closed.
Imo's is also noted for utilizing a popular St. Louis food: provel cheese. Provel cheese is what gives the pizza its flavor, besides the cracker-like crust. It was first produced in Wisconsin (year unknown) by the Hoffman Cheese Company (now part of Kraft). However, there are many accounts as to who first used it and who gave it its name. Every Imo's franchise uses an average 25,000 pounds of provel a year.
Today, there are 92 Imo's locations (as of this writing), all in the Midwest. They are regularly defined as the originators of 'St. Louis Style Pizza', or at least iconic in that pizza genre. Of course, there are other St. Louis style pizza chains that are competing with them, most notably Cecil Whittaker's. It is also believed they are the first to cut the pizza in squares. Not true, according to Margie Imo (in an interview with Fox 2/KTVI last year): 'It's a St. Louis thing. But no, we were not the first...'
Imo's Pizza Wikipedia link
Located at the corner of Shaw and Thurman streets, ST. LOUIS, MO, 63110
Cake artist: Theresa Hopkins