In this snapshot from July 1930, we see the shiny new J.C. Nichols Building. Its second floor housed offices for the Nichols Company.
Photo from State Historical Society of Missouri / J.C. Nichols Company Scrapbook

A PLAZA tradition had been started in 1925, when a single string of sixteen colored lights was hung over a doorway of a business in the Suydam Building. Within a few years, all buildings On The Plaza would be decorated, as shown in this circa-1935 image.
Photo from State Historical Society of Missouri / J.C. Nichols Company Scrapbook

In this photo from December 1939, we see a brightly-illuminated Plaza Theatre. On the bill this night was "Walt Disney's 'Fun And Fancy Free', in Technicolor with Bergen & McCarthy" (that would be Edgar Bergen with Charlie McCarthy, his ventriloquist dummy sidekick). 
Photo from State Historical Society of Missouri / J.C. Nichols Company Scrapbook

The Jack Henry Store, a men's clothier, opened its first On The Plaza location in 1937. In this circa-1945 photo, we see said store decorated for Halloween. 
Photo from State Historical Society of Missouri / J.C. Nichols Company Scrapbook

An interior view of the Jack Henry Store from 1947. This retail establishment would be a PLAZA tenant for 77 years. It closed its doors for good in May 2014.
Photo from State Historical Society of Missouri / J.C. Nichols Company Scrapbook