When you think of a mattress, you probably get images of a firm, white rectangle, filled with metal springs and topped with foam and cotton. Or, you might think of space age memory foam, latex mattresses, or other brand new sleep technology. But the mattress hasn't been like this forever. In fact, these modern mattresses haven't been around all that long at all. Before that, we slept on a wide variety of different surfaces and mattresses. Here's a look at some of the mattresses of the past, and how we got where we are today.