Greater Somalia beginning of the 20th century the concept of "Greater Somalia" started to be developed with the birth of the nation of Somalia, as a united country inhabited by all the Somali clans in their "Horn of Africa" areas. "Pan-Somalism" refers to the vision of reunifying these areas to form a single Somali nation. The pursuit of this goal has led to conflict: Somalia engaged after World War II in the Ogaden War with Ethiopia over the Ogaden region, and supported Somali insurgents against Kenya. Italians occupied the Benadir in 1890 and soon started to enlarge their "Somalia italiana" (Italian Somaliland):
Geology of Somalia and island arcs. In the Early Jurassic, the supercontinent Gondwana, which included Africa, began to break apart. The marine transgression of the Tethys Ocean flooded large parts of East Africa and Arabia and new sedimentary rock units were deposited. In the west of Somalia, the Cretaceous at the end of the Mesozoic brought crustal upwarping, which is preserved in the Yesomma Sandstone. Two major sedimentary basins began to form in Somalia during the Mesozoic, the Somali Coastal Basin and the Luuq-Mandera Basin, both filled with up to five kilometers of sedimentary rock. The basins formed due to the movements of