uhelné prázdniny (coal holiday).

Common in the fifties and sixties, schools were often closed for several days in the heart of winter due to shortages of coal and other heating material. Students last experienced a sustained closure in 1979, when a particularly severe cold stretch led to a two-week vacation. The problem was a combination of inefficient use of resources, lack of foreign currency to buy fuel, poor insulation of most buildings, and a tendency to overheat interiors in the winter. Those who were children at the time, however, remember these surprise vacations with fondness.