The Treaty of Versailles
The Treaty of Versailles started heavy territorial changes in the world.
Germany lost the Imperial Territory of Alsace-Lorraine (German: Reichsland Elsaß-Lothringen or Elsass-Lothringen, 14,500 square kilometers with 1,874,014 inhabitants) to France. Eupen and Malmedy (730 square kilometers, 280 sqmi) became parts of Belgium. The Saarland (1,910 kilometers with 812,000 inhabitants) would have a plebiscite over it's future in 35 years but first be a international Zone under Control of the League of Nations and a buffer between Germany and France.
The Rhineland (all remaining German Territory west of the Rhine, 32,930 square kilometers, 8,061,000 inhabitants) would be a international State under control and security of the League of Nations (20,000 Belgians, 14,000 British Forces and 25,000 to 40,000 French) for 15-20 years. If Germany paid it's reparations and complied to the Treaty of Versailles it's provinces were allowed to either return to Germany or France by plebiscite after 10 or 15 years.
The Schleswig plebiscite had 74.9% (75,431 votes) voters in the north voting to become Danish, while 25.1% (25,329 votes) voted to remain German, therefor northern Schleswig became a part of Denmark. In the east Germany would lose to the newly independent Poland (after plebiscites); most of Posen (18,553 square kilometers with 1,680,00 inhabitants south of the rivers Warte and Netze, leaving the railways over Nakel in the South and Danzig in the North to remaining German Eastern Prussia in German hands, but giving Poland the central railway hub around Posen), West Prussia (5,150 square kilometers 340,000 inhabitants south of the rivers Netze and Weichse -Kulmerland-, leaving the railways over Graudenz in the South in Polish hands) and parts of East Prussia (7,400 square kilometers, 412,00 inhabitants -Masuria-). The German Army would be limited to 100,000 soldiers in a maximum of seven infantry and three cavalry divisions. German navy was allowed six pre-dreadnought battleships and was limited to a maximum of six light cruisers (not exceeding 6,000 long tons/ 6,100 t), twelve estroyers (not exceeding 800 long tons/ 810 t) and twelve torpedo oats (not exceeding 200 long tons/ 200 t) and was forbidden submarines. The manpower of the navy was not to exceed 15,000 men, including manning for the fleet, coast defences, signal stations, administration, other land services, officers and men of all grades and corps. The number of officers and warrant officers was not allowed to exceed 1,500 men. Germany surrendered eight battleships, eight light cruisers, forty-two destroyers, and fifty torpedo boats for decommissioning. Thirty-two auxilary ships were to be disarmed and converted to merchant use. Germany would pay for the damage caused in Europe and the Colonies.
Austria-Hungary had to split into Austria and Hungary. Italy would gain South Tirol and parts of the coast around near Trieste. The Slovene minority of Carniola and Istriel remained inside Austria to be protected, but had the choice of a own plebiscite to become a independent state and a buffer between Austria and the Kingdom of Serbia. Austria would hold on to the German populated regions in Bohemia, Moravia and Silesia (Sudetenland). The Czech territories would gain it's independence from Austria. Galicia (Galizien) would became part of the newly independent Polish State. Austrians Amy would be limited to 30,000 soldiers.
Hungary lost the newly independent State of Slovakia (the Slovak populated regions), as well as the Carpathian-Ukraine that would become a part of them. Hungary would further lose Transylvania and parts of the Banat to Romania and parts of the Banat to the Kingdom of Serbia. The Kingdom of Serbia would gain Bosnia, Croatia-Slovonia, Dalmatia and pars of the Banat in total from Austria-Hungary. Hugarys Army would be limited to 35,000 soldiers.
On the Balkan Peninsula, the Greek State gained the southern Bulgarian coast till the Marica river up until Adrianopel. Bulgaria would even lose some western border regions to Serbia, while Greece also took the former Ottoman Aegean Islands. The Dardanelles would be permanently opened as a free passage to the ships and commerce of all nations under international guarantees and watch of the League of Nations. Bulgarias Army would be limited to 20,000 soldiers.
The Ottoman Empire (now Turkey) would loose the province around Smyrna to Greece, the Cilician Coast would go to France in the east and Italy in the west (up until the Greece territory) as Mandates of the League of Nation for these states. In the northeast Armenia and Kurdistan would be liberated as newly independent nations, with Armenia expanded westward to the Iskanderun at the Mediterranean Sea. The border between Armenia and Kurdistan would be the Armenian Taurus Mountains in the north, while Kurdistan would gain northern Mesopotamia and the Zagros Mountains with Kerkur and Mosul as major cities. In the western coast Britain gained Cyprus and Egypt for good, while France gained the Lebanon (Beirut) and the regions around Antakia and Ladikije as Mandates to protect the non-Arabian minorities there. Palestine became a Mandate under International Control (British and French Forces) of the League of Nations to guarantee free access to the Holy City of Jerusalem for every religion.
Britain expanded the Beirut region to control the Persian Gulf, while the rest of the former Ottoman Region would go to the newly independent Arabian Nation State (nor including the already southern and eastern British holdings on the Peninsula like Oman and Yemen), keeping the Allied promise to unite the majority of the Arabian lands in the North. At Dschakra and Ghaza the new Arabian State had two small corridors to even reach the Western Mediterranean. The Turkish Army would be limited to 50,000 soldiers.
In Africa the German Colonies became Mandates of the League of Nations. Togoland became part of Britain (34,000 Square Kilometers with 190,000 inhabitants) and France (52,000 Square Kilometers with 760,000 inhabitants). Cameron would seed 80,700 Square Kilometers with 690,000 inhabitants to Britain, 270,000 Square Kilometers with 79,000 inhabitants to France and 520,000 Square Kilometers with 1,540,000 inhabitants became part of the Italian Mandate of Cameron (that also gained a road and railroa connection to the Belgian Congo).
In South West Africa , the Dominion of South Africa gained the majority of Greater Namaland as a Mandate until the Walfish Bay, while Heroreland and Amboland became part of the Italian South West African Mandate of the League of Nations. Despite the Italian gains in the region France also gained access to the trade there and was allowed the same rights of trade, mining and investment then Italian companies in the Italia Manate, as well as access to the Zambezi River network.
In East Africa the Italians gained the coastal region around Darelsalam, from Lindi in the south to the Luvu River in the north. Portugal gained a small border region around Mikinda and Britain gained the western part of the former German Colony as a Mandate. This allowed the British to connect their northern, eastern and southern African Colonies from the Lake Victoria to Lake Tanganyika and Lake Nyassa.
In Asia, China regained Tsingtao/Quingdao, but Japan got trade and railway rights in Shantung in exchange. The Mariana, Caroline and Marshall Islands became a Japanese Mandate. The Bismark Archipelago additionally partly became a Japanese Mandate with Neu Mecklenburg (New Ireland) going to the Japanese Empire and Neu Pommern (New Britain) going to the British Empire (Australia). On New Guinea in Kaiser Wilhelms Land, the Japanese got parts of the Coast, while Australia gained most of the mountainous region up till the coast as well as the eastern coast from Marobe to Lae. The majority of the German Salamon Islands (including Bougainvillea) went to Australia, while Japan managed to get the smaller islands of Bouka, Green, Marqueen and Tasman.
This meant that the Treaty of Versailles left Italy as a major African Colonial Power and made Japan into a Pacific regional Power as well as one of the big global Naval Powers. Austria-Hungary and the Ottoman Empire stopped to exist, while the German Empire lost all it's colonies overseas as well as some border regions in Europe. But with the ongoing Civil Wars and Revolutions in Russia, Finland and China the world was far from peaceful and secure by now. Many of the Entente Nations truly thought about using the German Army together with their own forces to help out the White Russian forces fighting the Soviet Red Army Forces, before their Bolshevik, Socialist and Communist Revolution would spread across the borders of the former Russian Empire. At the same time the League of Nations refused to take sides in a intern Civil War of a Nation, while the European Powers were split about aiding the Whites and fighting the Reds.
But even the victories powers were disappointed in the Treaty of Versailles. France ambitions to rise as the new hegemonic power in Europe were stopped by the British, Italians hopes to gain Dalmatia and control the Adrian Sea had not be respected. Germany believed the Treaty to be unfair. Greater Serbia, Greece and Romania supported it fully, while their Balkan Neighbors Hungary and Bulgaria hoped for revisions just like Germany. While some former Entente Powers became involved in the Russian Civil War, Belgium, Britain and France fought the 60,000 men strong Red Ruhr Army, from toppling the Rhineland into a Communist Regime. Both events weaken Britain's military power in the Irish War for Independence. Soon the British Parliament would think about splitting northern and southern Ireland (s a new internal independent member of the British Empire). In the Polish-Soviet War, the new state of Poland looses the Ukraine, but expands it's territory eastwards in a Peace Treaty with the Soviets. The United States of America happily that their wishes were respected at Versailles, join the League of Nations to protect this peace. Latvia and Estonia gained their independence from the Bolshevik Russian forces and fell under influence of the Polish-Lithuanian Commonwealth. In the Caucasus Region Georia and Azerbaijan gained their independence thanks to Entente/ Alied Forces. In Siberia Japanese, White and Allied forces tried to stop the Bolsheviks, while China fell into it's own internal civil war. The Mexican Revolution continued and the young Turkish State continued the 1919 began War of Independence against the Allies (Greeks in the West, Armenia and Kurdistan in the Est, France and Italy in the South and the United Kingdom and Italy in Constantinople (Istanbul).
The World in 1920
The question was what should the League of Nations do against the Turkish aggression and ignoring of the Treaty of Versailles?