The oldest known fishing net is the net of Antrea, found with other fishing equipment in the Karelian town of Antrea. The net was made from willow, and dates back to 8300 BC. Fishing nets have not evolved greatly, and many contemporary fishing nets would be recognized for what they are in Neolithic times. Early nets were woven from grasses, flaxes and other fibrous plant material. Later cotton was used. Modern nets are usually made of artificial polyamides like nylon, although nets of organic polyamides such as wool or silk thread were common until recently. Some types of fishing nets, like seine and trammel, need to be kept hanging vertically in the water by means of floats at the top (you can see some floats in this fun new puzzle). Floats come in different sizes and shapes and are made from various light "corkwood"-type woods.