Security concerns for the nation's electrical grid are being raised after a substation attack in North Carolina. This past February, Bill Whitaker reported on the vulnerabilities in the system that provides our electricity. "60 Minutes" is the most successful television broadcast in history. Offering hard-hitting investigative reports, interviews, feature segments and profiles of people in the news, the broadcast began in 1968 and is still a hit, over 50 seasons later, regularly making Nielsen's Top 10. Subscribe to the “60 Minutes” YouTube channel: http://bit.ly/1S7CLRu Watch full episodes: http://cbsn.ws/1Qkjo1F Get more “60 Minutes” from “60 Minutes: Overtime”: http://cbsn.ws/1KG3sdr Follow “60 Minutes” on Instagram: http://bit.ly/23Xv8Ry Like “60 Minutes” on Facebook: http://on.fb.me/1Xb1Dao Follow “60 Minutes” on Twitter: http://bit.ly/1KxUsqX Subscribe to our newsletter: http://cbsn.ws/1RqHw7T Download the CBS News app: http://cbsn.ws/1Xb1WC8 Try Paramount+ free: https://bit.ly/2OiW1kZ For video licensing inquiries, contact: licensing@veritone.com