Which wars resulted in significant territorial gains or losses?

Several wars resulted in significant territorial gains or losses, including the Second World War, the American Civil War, and the Sino-Japanese War.

The Second World War (1939-1945) was a global conflict that resulted in significant territorial changes. Germany, under Adolf Hitler, annexed Austria and the Sudetenland region of Czechoslovakia, and later invaded Poland, triggering the war. As the war progressed, Germany occupied much of Europe. However, the tide turned, and by the end of the war, Germany had lost all its territorial gains. The Soviet Union also made significant territorial gains in Eastern Europe, which it maintained after the war. The end of the war also saw the division of Germany and Berlin into four zones controlled by the Allies (the United States, the United Kingdom, France, and the Soviet Union), marking the beginning of the Cold War.

The American Civil War (1861-1865) was a significant conflict in the United States that resulted in substantial territorial changes. The war began when several southern states seceded from the Union to form the Confederate States of America, leading to a division of the country. The Union's victory in the war led to the abolition of slavery and the reintegration of the Confederate states into the Union, effectively restoring the territorial integrity of the United States.

The First Sino-Japanese War (1894-1895) resulted in significant territorial losses for China and gains for Japan. The war was fought over control of Korea, which was a tributary state of China at the time. Japan's victory in the war led to the Treaty of Shimonoseki, which recognised Korea's independence and ceded Taiwan and the Pescadores Islands to Japan. This marked the beginning of Japan's imperial expansion in East Asia.

In conclusion, wars often result in significant territorial changes, either through conquest, annexation, or treaties. These changes can have long-lasting impacts on the countries involved and the global geopolitical landscape.