A deadly cold snap is hitting the US Midwest, forcing flight cancellations and causing major travel disruption.
More than 1,500 flights have been cancelled at Chicago’s two main airports and rail operator Amtrak has shut down its services.
The Arctic weather, known as a polar vortex, has killed at least eight people across several states.
Temperatures fell to -30C in Chicago and -37C in North Dakota.
States of emergency have been declared in the Midwestern states of Wisconsin, Michigan, Illinois, Alabama and Mississippi.
