The history of today's dollhouses can be traced back about four hundred years to the baby house display cases of Europe, which showed idealized interiors. Smaller dollhouses with more realistic exteriors appeared in Europe in the 18th century. Early dollhouses were all handmade, but following the Industrial Revolution and World War II, they were increasingly mass-produced and became more standardized and affordable. Dollhouses can range from simple boxes stacked together used as rooms for play, to multi-million dollar structures displayed in museums.