As I was looking around for some digital images of the Beijing Olympic stadium, I came across this.Under the heading “GoogleEarth adds historical photos” in the Time photogallery news. A small selection of photos were presented as a slide set and they showed some great examples of “then and now” With a vast trove of images from the past, the massive cartographic search tool lets users travel back in Earth’s  travel back in Earth’s time. I wanted some pictures of Olympic Stadiums. So here is what turned up in the slide showBeijing Olympic Stadium-2005 and nextBeijing Olympic Stadium 2008The first photos in the slide set were of the Aral Sea; 1. as it looked in 1973, before the onset of desertification and 2. The Aral Sea in 2008. “Scientists estimate that over the last four decades, the sea’s surface area has shrunk by approximately 60%, and its volume by 80%.”The set here is worth looking through and I can see photographs such as these being useful in Geography. The students having the option to view, visually, any change in the earth, is much more powerful than just reading about the statistics. Changes to neighbourhoods, to different geographical features, changes in  land use and the like can be seen in these photographs.After having a look at these, I am going to have a look through the images to see what other photos are available and make some time to talk with the geography teachers.You will need to download Google Earth 5.0 at http://earth.google.comBy default, Google Earth displays most up-to-date imagery available. You can view historical imagery so that you can see how places have changed over time.There is a blog post , in Watts up with that, that offers explanation of how to  access historical imagery.