Final answer:
The Grand Ole Opry is a historic radio show that started in the 1920s and is known as the most significant in country music history, being the longest-running live broadcast radio show in the US.
Step-by-step explanation:
The radio show called the Grand Ole Opry went on the air in the 1920s and became the most important radio show in the history of country music. WSM in Nashville started broadcasting this live music show, which became an iconic symbol of country music and holds the title of the longest live broadcast radio show in U.S. history. The power of radio during this era was tremendous, notably influencing American culture by bringing news, and entertainment, and creating a national identity through widely shared programming.