If a thin walled closed tin-can containing only steam is cooled, then?

Bill Nye the Science Guy (local science teacher here in Western Washington State) does a great demo of this with a gallon metal can like paint thinner comes in. He boils a little water in the can, shuts off the heat and closes the lid. When the steam condenses by cooling, the air pressure crushes the can. Great. He once did this with a 55-gallon oil drum! Fantastic!