The 1800s (pronounced "eighteen-hundreds") was a decade of the Gregorian calendar that began on 1 January 1800, and ended on 31 December 1809.
The term "eighteen-hundreds" could also mean the entire century from 1 January 1800 to 31 December 1899 (the years beginning with "18"), and is almost synonymous with the 19th century (1801–1900).
The decade was a period of drastic change. The advancements of the previous three decades towards the end of the 18th century had propelled the Industrial Revolution into a global movement, with entire wars fought with the newly developed technologies – creating an impetus to imperialist campaigns across Africa and Asia, as well as the counter-movement on Latin America later on.