NERC conducted its sixth biennial security exercise, GridEx VI, on November 16–18, 2021. This grid security, emergency, and response exercise was developed, managed, and delivered by NERC’s Electricity Information Sharing and Analysis Center (E-ISAC). The E-ISAC divided play into two portions: Distributed Play, held on November 16–17, 2021, provided the opportunity for operational participants across North America to exercise the resilience of the electricity system. The Executive Tabletop, held on November 18, 2021, convened industry executives and government leadership from the United States and Canada to explore the challenges presented by a severe cyber and physical attack against the grid.