In 1923, the Missouri Supreme Court declared the 1918 residential zoning ordinance unconstitutional (see City of St. Louis v. Evraiff, 256 S.W. 489 (Mo. 1923)) and businesses began to purchase lots in the area. What the tornado of 1896 had begun, and the encroachment of gas stations and grocery stores continued, the Great Depression accelerated. By the end of World War II, the Square’s half-century of decline was complete. At this time, the neighborhood that was once the jewel of St. Louis had reached the low point in its history by becoming “a pocket ghetto of the unfortunate and poor,” known as “Slum D.”