In 1837, William IV died of liver disease and the throne passed to the next in line, his 18-year old niece Victoria (1819-1901), although she did not inherit the Kingdom of Hanover, where the Salic Law forbid women to rule.
Victoria didn't expect to become queen, was still unmarried and inexperienced in politics, and had to rely on her Prime Minister, Lord Melbourne (1779-1848), after whom the Australian city is named. She finally got married to her first cousin, Prince Albert of Saxe-Coburg-Gotha (1819-1861), and both were respectively niece and nephew of the first King of the Belgians, Leopold I (of Saxe-Coburg-Gotha).
Prince Albert organised the Great Exhibition (the first World Fair) in 1851, and the profits were used to found the great South Kensington Museum (later renamed the Victoria and Albert Museum) in London.
Britain asserted its hegemony on virtually every part of the globe, although this resulted in numerous wars, as for example the Opium Wars (1839-42 & 1856-60) with Qing China, or the Boer Wars (1880-81 & 1899-1902) with the Dutch-speaking settlers of South Africa.
In 1854, the the United Kingdom was brought into the Crimean War (1854-56) on the side of the Ottoman Empire and against Russia. One of the best known figure of that war was Florence Nightingale (1820-1910), who fought for the improvement of the women's condition and pioneered modern nursing (see Claydon House).
In 1861, Albert died prematurely at the age of 42. Victoria was devastated and retired in a semi-permanent state of mourning. She nevertheless started a romantic relationship with her Scottish servant John Brown (1826-1883), and there were even talks of a secret marriage. This episode of Victoria's life has been the object of the film Mrs Brown.
The latter years of her reign were dominated by two influential Prime Ministers, Benjamin Disraeli (1808-1881) and his rival William Ewart Gladstone (1809-1898). The former was the favourite of the Queen, and crowned her "Empress of India" in 1876, in return of which Victoria creating him Earl of Beaconsfield. Gladstone was a liberal, and often at odd with both Victoria and Disraeli, but the strong support he enjoyed from within his party kept him in power for a total of 14 years between 1868 and 1894. He legalised trade unions, advocated both universal education and universal suffrage (well, at least for men).
Queen Victoria was to have the longest reign of any British monarch (64 years), but also the most glorious, as she ruled over 40% of the globe and a quarter of the world's population.
The Two World Wars
Victoria's numerous children married in about all European Royal families, which owned her the affectionate title of "grandmother of Europe". Her son, Edward VII (1841-1910) was the uncle of German Emperor Wilhelm II, Tsar Nicholas II of Russia, King Alphonso XIII of Spain, and Carl Eduard, Duke of Saxe-Coburg-Gotha, while George I of the Hellenes and King Frederick VIII of Denmark were his brothers-in-law; and King Albert I of Belgium, Manuel II of Portugal, King Ferdinand of Bulgaria, Queen Wilhelmina of the Netherlands, and Prince Ernst August, Duke of Brunswick-Lüneburg, were his cousins.
The alliances between these related monarchs escalated in the Great War (WWI) of 1914-1918 when Archduke Franz Ferdinand of Austria was assassinated in Sarajevo, and Austria declared war on Serbia, which in turn was allied to France, Russia and the UK. The First World War left over 9 million dead (including nearly 1 million Britons) throughout Europe, and financially ruined most of the countries involved. The monarchies in Germany, Austria, Russia and the Ottoman Empire all fell, and the map of central and eastern Europe was redesigned.
The consequences in Britain were disillusionment with the government and monarchy, and the creation of the Labour Party. The General Strike of 1926 and the worsening economy led to radical political changes, and women were granted the same universal suffrage as men (from age 21 instead of previously 30) in 1928.
In 1936, Edward VIII (1894-1972) succeeded to his father George V, but abdicated the same year to marry Wallis Simpson, a twice divorced American woman. His brother then unexpectedly became George VI (1895-1952) after the scandal.
Nazi Germany was becoming more menacing as Hitler grew more powerful and aggressive. Finally Britain and France were forced to declare war on Germany after the invasion of Poland in September 1939, and so started the Second World War. The charismatic Winston Churchill (1874-1965) became the war-time Prime Minister in 1940 and his speeches encouraged the British to fight off the attempted German invasion. In one of his most patriotic speeches before the Battle of Britain (1940), Churchill address the British people with "We shall defend our island, whatever the cost may be, we shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender." And indeed, Britain did not surrender.