Mountains, lakes isthmus archipelagos
a war between the allies (Russia, France, British Empire, Italy, United States, Japan, Rumania, Serbia, Belgium, Greece, Portugal, Montenegro) and the Central Powers (Germany, Austria-Hungary, Turkey, Bulgaria) from 1914 to 1918.
The immediate cause of its fall was pressure by the Ottoman Turks. ... In 1204, the Fourth Crusade conquered Constantinople, partly because the Venetians wanted to eliminate the Byzantines as competition in trading matters. Hope this helps