Sea ice in the polar regions of the Arctic and Antarctic covers approximately seven percent of our planet, which is bigger than the total area of Europe. These seven percent have a relatively large impact on global climate. Sea ice is particularly driving heat and freshwater exchange of the polar oceans and therefore plays a key role in the earth's climate system. Structure, volume and spatial extent of sea ice are highly differentiated and variable. As a result of these physical characteristics, sea ice has great effects on the energy budget of the earth's surface. Sea ice is highly complex, but at the same time it is certainly one of the most interesting and influential materials on our planet. Additionally, sea ice is an especially fascinating habitat that is essential for the ecosystem of the polar regions.