A major power blackout struck the northeastern United States and parts of Canada, impacting approximately 50 million people across multiple states and provinces. The blackout, one of the largest in North American history, started in the late afternoon and extended into the early evening on a hot summer day. The incident began when a failure in the monitoring system within the electrical grid allowed a series of failures to cascade through the system, causing the loss of transmission lines and leading to widespread outages.

Cities like New York, Cleveland, and Toronto were particularly affected, with traffic lights out and public transport systems rendered inoperative. People were left stranded in elevators and subways, creating a chaotic atmosphere as emergency services were inundated with calls for assistance. Businesses halted operations, and people were forced to evacuate ongoing events, as the lack of power resulted in darkness and confusion across the region.

The power outage lasted for up to two days in some areas before full service was restored. Investigations following the blackout revealed vulnerabilities in the grid and underscored the importance of robust systems management and infrastructure investment. The experience led to a reevaluation of energy policies and operational protocols, with an emphasis on improving grid reliability and preventing similar occurrences in the future.