Mesmerizing video shows a ship busting through the ice as it travels along the frozen Chicago River.

Aerial views showed the river frozen over this week as the Windy City and the rest of the Midwest were blasted with arctic winds ushered in by a polar vortex.

As the mercury dipped to -23 degrees at Chicago’s O’Hare International Airport on Wednesday, the coldest since that date in 1966, swirling smoke was also spotted floating above the river.

That effect, called “steam fog” or “sea smoke,” is actually water vapor formed when cold air moves over warmer water.