Find out when glass blocks were invented.
Glass blocks were invented in Europe in 1931 as thin blocks of glass supported by a grid. They have been in and out of favor since they were introduced. They are small, the largest being 12 inches by 12 inches (30 centimeters by 30 centimeters).
They offer the following advantages: they allow natural light to filter through, but their patterns can afford privacy; they have the insulating value of a 12 inch-thick (30 centimeters) concrete wall; they absorb outside noise; and they are much more secure than ordinary flat glass.