While the exact size of the original desert is unknown, some geologists believe that the Croatian Sahara used to encompass an area of thousands of acres. The Croatian desert was formed during the Ice age. During this period, the rocks in the nearby Alps in Slovenia and Austria were frozen and ground into sand dust. This sand was then deposited into nearby lakes, which then transported the sand particles into rivers and streams. Towards the end of the ice age when the ice started to melt, these rivers increased in size and began transporting all of the sand towards the east. Once the sand reached the are of Djurdjevac, the slow water current cause the sand to build up in the area which is today the Croatian Sahara. As humans began to populate the area, farming and natural green land began to over take the desert. The cultivation of the land along with the change in weather cause the Croatian Desert to decrease to the smaller size that it is today.