The Wars of German Unification (comprising the Danish War, Austro-Prussian War, and Franco-Prussian War) between 1864 and 1871 led to the establishment of a united and powerful German Empire under Prussian leadership. This shifted the balance of power in Europe dramatically. The Austro-Prussian War of 1866 effectively sidelined Austria, ensuring it had no role in German affairs. The subsequent Franco-Prussian War in 1870-71 saw the defeat of France, the primary continental power, leading to the proclamation of the German Empire in 1871. This new German Empire, industrially robust and militarily potent, changed the European power dynamics, challenging British and French dominance and setting the stage for future conflicts.

The Boer Wars played a pivotal role in shaping the future political landscape of South Africa. The wars were fought between the British Empire and the two Boer states – the Orange Free State and the Transvaal Republic. After the second war ended in 1902 with the Treaty of Vereeniging, the Boer republics came under British control, with a promise of eventual self-governance. This led to the establishment of the Union of South Africa in 1910, uniting the former Boer republics with British colonies. While the union set the stage for South Africa's independence in 1961, the socio-political legacies of these wars, particularly concerning racial and cultural differences, also sowed the seeds for the Apartheid policy, which came into effect in 1948 and institutionalised racial segregation and discrimination.

The War of the Spanish Succession (1701-1714) was crucial for maintaining the balance of power in Europe. The war began due to concerns that the Bourbon family, if they secured the Spanish throne, would effectively unite Spain and France, creating a superpower that could dominate Europe. The conflict pitted France and Spain against a coalition of European powers, including Britain, the Dutch Republic, and Austria. The subsequent Treaty of Utrecht in 1713 ensured that the French and Spanish crowns remained separate. By preventing a Franco-Spanish superstate, the treaty preserved the delicate balance of power in Europe, ensuring no single nation could dominate the continent.

The Opium Wars, fought between Britain and Qing Dynasty China, significantly bolstered British colonial ambitions in Asia. Following China's defeat in the First Opium War (1839-42), the Treaty of Nanking was signed, which ceded the island of Hong Kong to Britain. Additionally, five "Treaty Ports" were opened to foreign trade, and China had to pay substantial war indemnities. After the Second Opium War (1856-60), the Treaty of Tientsin allowed more ports for trade and the legalisation of opium, further increasing Britain's economic influence. The wars marked the beginning of China's "Century of Humiliation" and significantly expanded Britain's imperial footprint in Asia.

The Treaty of Versailles in 1919 had a profound impact on the territorial boundaries of Europe following WWI. The most significant changes were imposed upon Germany. Alsace and Lorraine, which Germany had taken from France in 1871, were returned. The Saar Basin was placed under the administration of the League of Nations for 15 years. The provinces of West Prussia and Poznan went to Poland, while the city of Danzig, with its large German population, became a free city. Furthermore, to prevent future invasions, the Rhineland was demilitarised. The territorial changes aimed to weaken Germany and prevent future conflicts, but many argue that they sowed the seeds for WWII by stoking German resentment.