19th century

The 19th century began on January 1, 1801 and ended on December 31, 1900, according to the Gregorian calendar. During the 19th century, the Spanish, Portuguese, Chinese, and Ottoman empires began to crumble, the Holy Roman Empire was dissolved, and the Mughal empire collapsed.

After the Napoleonic Wars, the British Empire became the world's leading power, controlling one quarter of the world's population and one third of the land area. It enforced a Pax Britannica, encouraged trade, and battled rampant piracy. During this time the 19th century was an era of widespread invention and discovery, with significant developments in the understanding or manipulation of mathematics, physics, chemistry, biology, electricity, and metallurgy largely setting the groundworks for the comparably overwhelming and very rapid technological innovations which would take place the following century.

Modest advances in medicine and the understanding of human anatomy and disease prevention were also applicable to the 1800s, and were partly responsible for rapidly accelerating population growth in the western world. The introduction of railroads provided the first major advancement in land transportation for centuries, and their placement and application radically altered the ways people could live and rapidly and reliably obtain necessary commodities, fueling major urbanization movements in countries across the globe. Numerous cities worldwide surpassed populations of 1,000,000 or more during this century. The last remaining undiscovered landmasses of Earth, largely pacific island chains and atolls, were discovered during this century, and with the exception of the extreme zones of the Arctic and Antarctic, accurate and detailed maps of the globe were available by the 1890s.

Slavery was greatly reduced around the world. Following a successful slave revolt in Haiti, Britain forced the Barbary pirates to halt their practice of kidnapping and enslaving Europeans, banned slavery throughout its domain, and charged its navy with ending the global slave trade. Britain abolished slavery in 1834, America's 13th Amendment following their Civil War abolished slavery there in 1865, and in Brazil slavery was abolished in 1888 (see Abolitionism). Similarly, serfdom was abolished in Russia.

The 19th century was remarkable in the widespread formation of new settlement foundations which were particularly prevalent across North America and Australasia, with a significant proportion of the two continents' largest cities being founded at some point in the century.