IYD&D

2006 International Year of Deserts & Desertification

More info from Education Network of Australia on Deserts

A flickr group for IYDD

Optical illusions links

Websites with lots of optical illusions and their explanations.

http://www.planetperplex.com/en/optical_illusions.html

http://www.grand-illusions.com/opticalillusions/

http://www.grand-illusions.com/opticalillusions/index02.shtml