Modern era

Long nineteenth century

The long nineteenth century traditionally starts with the French Revolution in 1789, and lasts until the outbreak of World War I in 1914. It saw the global spread of the Industrial Revolution, the greatest transformation of the world economy since the Neolithic Revolution. The Industrial Revolution began in Great Britain around 1770 and used new modes of production—the factory, mass production, and mechanization—to manufacture a wide array of goods faster while using less labor than previously required.

Industrialization raised the global standard of living but caused upheaval as factory owners and workers clashed over wages and working conditions. Along with industrialization came modern globalization, the increasing interconnection of world regions in the economic, political, and cultural spheres. Globalization began in the early 19th century and was enabled by improved transportation technologies such as railroads and steamships.

European empires lost territories in Latin America, which won independence by the 1820s through military campaigns, but expanded elsewhere as their industrial economies gave them an advantage over the rest of the world. Britain gained control of the Indian subcontinent, Burma, Malaya, North Borneo, Hong Kong, and Aden; the French took Indochina; and the Dutch cemented their rule over Indonesia. The British also colonized Canada, Australia, New Zealand, and South Africa with large numbers of British colonists emigrating to these colonies.

Russia colonized large pre-agricultural areas of Siberia. The United States completed its westward expansion, establishing control over the territory from the Atlantic to the Pacific coast.

In the late 19th century to early 20th century, the European powers, driven by the Second Industrial Revolution, rapidly conquered and colonized almost the entirety of Africa. Only Ethiopia and Liberia remained independent. Imperial rule in Africa involved many atrocities such as those in the Congo Free State and the Herero and Nama genocide.

Within Europe, economic and military competition fostered the creation and consolidation of nation-states, and other ethno-cultural communities began to identify themselves as distinctive nations with aspirations for their own cultural and political autonomy. This nationalism became important to peoples across the world in the 19th and 20th centuries. In the first wave of democratization, between 1828 and 1926, democratic institutions were established in 33 countries worldwide.

Most of the world abolished slavery and serfdom in the 19th century. Over several decades, beginning in the late 19th century and continuing throughout the 20th, in many countries the women's suffrage movement won women the right to vote, and women began to enjoy greater access to education and to professions beyond domestic employment.

In response to encroachment by European powers, several countries undertook programs of industrialization and political reform along Western lines. The Meiji Restoration in Japan led to the establishment of a colonial empire, while the tanzimat reforms in the Ottoman Empire did little to slow the Ottoman decline. China achieved some success with its Self-Strengthening Movement but was devastated by the Taiping Rebellion, history's bloodiest civil war, which between 1850 and 1864 killed 20–30 million people.

By the end of the century, the United States became the world's largest economy. During the Second Industrial Revolution, new technological advances, involving electric power, the internal combustion engine, and assembly-line manufacturing, further increased productivity. Technological innovations also provided new avenues for artistic expression through the media of photography, sound recording, and film.

Meanwhile, industrial pollution and environmental degradation accelerated drastically. Balloon flight had been invented in the late 18th century, but it was only at the beginning of the 20th century that powered aircraft were developed.

World wars

This transformation was catalyzed by wars of unparalleled scope and devastation. World War I was a global conflict from 1914 to 1918 between the Allies, led by France, Russia, and the United Kingdom, and the Central Powers, led by Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria. It had an estimated death toll ranging from 10 to 22.5 million and resulted in the collapse of four empires – the Austro-Hungarian, German, Ottoman, and Russian Empires. Its new emphasis on industrial technology had made traditional military tactics obsolete.

The Armenian, Assyrian, and Greek genocides saw the systematic destruction, mass murder, and expulsion of those populations in the Ottoman Empire. From 1918 to 1920, the Spanish flu caused the deaths of at least 25 million people.

In the war's aftermath a League of Nations was formed in the hope of averting future international conflicts; and powerful ideologies rose to prominence. The Russian Revolution of 1917 created the first communist state, while the 1920s and 1930s saw fascist political parties gain control in Italy and Germany. The Soviet Union, during Joseph Stalin's rule from 1924 to 1953, committed countless atrocities against its own people, including mass purges, forced labor camps, and widespread famine caused by state policies.

Ongoing national rivalries, exacerbated by the economic turmoil of the Great Depression, helped precipitate World War II. In that war, the vast majority of the world's countries, including all the great powers, fought as part of two opposing military alliances: the Allies and the Axis. The leading Axis powers were Germany, Japan, and Italy; while the United Kingdom, the United States, the Soviet Union, and the Republic of China were the "Big Four" Allied powers.

The militaristic governments of Germany and Japan pursued an ultimately doomed course of imperialist expansionism. In the course of doing so, Germany orchestrated the genocide of 6 million Jews in the Holocaust, and of millions of non-Jews across German-occupied Europe, while Japan murdered millions of Chinese. The war also saw the introduction and use of nuclear weapons, which brought unprecedented destruction and ultimately led to Japan's surrender. Estimates of the war's total casualties range from 55 to 80 million.

Contemporary history

When World War II ended in 1945, the United Nations was founded in the hope of preventing future wars, as the League of Nations had been formed following World War I. The United Nations championed the human rights movement, in 1948 adopting a Universal Declaration of Human Rights. Several European countries formed what would evolve into a 27-member-state economic and political community, the European Union.

World War II had opened the way for the advance of communism into Eastern and Central Europe, China, North Korea, North Vietnam, and Cuba. To contain this advance, the United States established a global network of alliances. The largest, NATO, was established in 1949 and eventually grew to include 32 member states. In response, in 1955 the Soviet Union and its Eastern European allies formed the Warsaw Pact mutual-defense treaty.

The United States and the Soviet Union emerged as the primary global powers in the aftermath of World War II. Both nations harbored deep suspicions and fears about the global spread of the other's political-economic system — capitalism for the United States and communism for the Soviet Union. This mutual distrust sparked the Cold War, a 45-year stand-off and arms race between the two nations and their allies.

With the development of nuclear weapons during World War II and their subsequent proliferation, all of humanity was put at risk of nuclear war between the two superpowers, as demonstrated by many incidents, most prominently the October 1962 Cuban Missile Crisis. Such war being viewed as impractical, the superpowers instead waged proxy wars in non-nuclear-armed Third World countries. The Cold War ended peacefully in 1991 after the Soviet Union collapsed, partly due to its inability to compete economically with the United States and Western Europe.

Cold War preparations to deter or fight a third world war accelerated advances in technologies that, though conceptualized before World War II, had been implemented for that war's exigencies, such as jet aircraft, rocketry, and computers. In the decades after World War II, these advances led to jet travel; artificial satellites with innumerable applications, including GPS; and the Internet, which in the 1990s began to gain traction as a form of communication. These inventions revolutionized the movement of people, ideas, and information.

The second half of the 20th century also saw groundbreaking scientific and technological developments such as the discovery of the structure of DNA and DNA sequencing, the worldwide eradication of smallpox, the Green Revolution in agriculture, the discovery of plate tectonics, the moon landings, crewed and uncrewed exploration of space, advances in energy technologies, and foundational discoveries in physics phenomena ranging from the smallest entities (particle physics) to the greatest (physical cosmology).

These technical innovations had far-reaching effects. During the 20th century the world's population quadrupled to six billion, while world economic output increased by a factor of 20. Toward the end of the 20th century, the rate of population growth started to decline, in part because of increased awareness of family planning and better access to contraceptives. Parts of the world now have sub-replacement fertility rates.

Public health measures and advances in medical science contributed to a sharp increase in global life expectancy at birth from about 31 years in 1900 to over 66 years in 2000. In 1820, 75% of humanity lived on less than one dollar a day, while in 2001 only about 20% did. At the same time, economic inequality increased both within individual countries and between rich and poor countries. The importance of public education had already begun to increase in the 18th and 19th centuries but it was not until the end of the 20th and the beginning of the 21st century that compulsory free education was provided to most children worldwide.

In China, the Maoist government implemented industrialization and collectivization policies as part of the Great Leap Forward (1958–1962), leading to the starvation deaths (1959–1961) of 30–40 million people. After these policies were rescinded, China entered a period of economic liberalization and rapid growth, with the economy expanding by 6.6% per year from 1978 to 2003.

In the postwar decades, in a process of decolonization, the African, Asian, and Oceanian colonies of European empires won their formal independence. Postcolonial states in Africa struggled to grow their economies, facing structural barriers such as reliance on the export of commodities rather than manufactured goods. Sub-Saharan Africa was the world region hit hardest by the HIV/AIDS pandemic of the late 20th century. Moreover, Africa experienced high levels of violence, as in the Second Congo War (1998–2003), the deadliest conflict since World War II.

The Near East experienced numerous conflicts, including the Iran-Iraq War, the first and second Gulf wars, and the Syrian Civil War, as well as tensions and conflicts between Israel and Palestine. Development efforts in Latin America were hindered by over-reliance on commodity exports and by political instability, some of it caused by United States involvement in regime change in Latin America.

The early 21st century was marked by growing economic globalization and integration, which brought both benefits and risks to interlinked economies, as exemplified by the Great Recession of the late 2000s and early 2010s. Communications expanded, with smartphones and social media becoming ubiquitous worldwide by the mid-2010s. By the early 2020s, artificial intelligence systems improved to the point of outperforming humans at many circumscribed tasks.

The influence of religion continued to decline in many Western countries, while some parts of the Muslim world saw the rise of fundamentalist movements. In 2020, the COVID-19 pandemic substantially disrupted global trading, caused recessions in the global economy, and spurred cultural paradigm shifts.

Concerns grew as existential threats from environmental degradation and global warming became increasingly evident, while mitigation efforts, including a shift to sustainable energy, made gradual progress.