Task: Question Generation
Input (English): Passage: In the early 20th century, Tulsa was home to the "Black Wall Street", one of the most prosperous black communities in the United States at the time. Located in the Greenwood neighborhood, it was the site of the Tulsa Race Riot, one of the nation's worst acts of racial violence and civil disorder, with whites attacking blacks. Sixteen hours of rioting on May 31 and June 1, 1921, was ended only when National Guardsmen were brought in by the Governor. An official report later claimed that 23 black and 16 white citizens were killed, but other estimates suggest as many as 300 people died, most of them black. Over 800 people were admitted to local hospitals with injuries, and an estimated 10,000 black people were left homeless as 35 city blocks, composed of 1,256 residences, were destroyed by fire. Property damage was estimated at $1.8 million. Efforts to obtain reparations for survivors of the violence have been unsuccessful, but the events were re-examined by the city and state in the early 21st century, acknowledging the terrible actions that had taken place.
In 1925, Tulsa businessman Cyrus Avery, known as the "Father of Route 66," began his campaign to create a road linking Chicago to Los Angeles by establishing the U.S. Highway 66 Association in Tulsa, earning the city the nickname the "Birthplace of Route 66". Once completed, U.S. Route 66 took an important role in Tulsa's development as the city served as a popular rest stop for travelers, who were greeted by Route 66 icons such as the Meadow Gold Sign and the Blue Whale of Catoosa. During this period, Bob Wills and his group, The Texas Playboys, began their long performing stint at a small ballroom in downtown Tulsa. In 1935, Cain's Ballroom became the base for the group, which is largely credited for creating Western Swing music. The venue continued to attract famous musicians through its history, and is still in operation today.
Output (English): Who led the group that had their base at Cain's Ballroom beginning in 1935?