Sept. 20 has been a big day in country music history. Breakthrough Hits and MilestonesBreakthroughs and milestones for Sept. 20 include:2018: The wildly successful Carrie Underwood received a star on the famous Hollywood Walk of Fame. 2019: Thomas Rhett headlined the historic Madison Square Garden in New York City on Sept. 20. Fans traveled to Louisville, Kentucky, to attend the mixed-genre Bourbon & Beyond music festival. During the premiere of the theatrical production of Dolly Parton's 9 to 5, there was a technical glitch that delayed the Sept. 20 show at the Ahmanson Theatre in Los Angeles, California.