In 1920, '''KDKA''' in [[Pittsburgh]], [[Pennsylvania]], became the first commercial radio station, and radio quickly developed into the center of entertainment for families. Use of radio spread most quickly in the [[United States]]. | In 1920, '''KDKA''' in [[Pittsburgh]], [[Pennsylvania]], became the first commercial radio station, and radio quickly developed into the center of entertainment for families. Use of radio spread most quickly in the [[United States]]. |