Platform shoes are shoes that have extremely dense soles at least four inches high. They are often made out of plastics, rubber or cork. Platform shoes were first worn during the Ancient era. They are known to add height to whoever is wearing them. The shoes are oftentimes worn to avoid coming in contact with urban street filth, grime and muck. These shoes were very popular between the 1930s and the 1980s in the United States, Europe and the United Kingdom. They were worn mostly by girls or young women, although middle-aged or elderly women sometimes wear the shoes. Comfort platforms were invented during the disco music era, and would be designed to mix added heights and sneaker style or orthotic comforts. The fad eventually fizzled out during the late 1980s and early 1990s, though by then people of all ages, particularly girls and young to middle-aged women, wore the shoes.