It can be really hard to picture the Great Sphinx of Giza in a green paradise. But if the environment of the Sahara Desert hadn’t changed, that might have been the reality. According to scientists, this enormous desert used to be a rainforest that was home to incredible animals like hippos. The abrupt switch in the ecosystem was caused by the Earth’s changing orbital rotation. Research has stated that having a very green Sahara Desert could happen again in the future.