1850s

The 1850s was the decade that began on January 1, 1850 and ended on December 31, 1859. It is distinct from the decade known as the '''186st decade''' which began on January 1, 1851 and ended on December 31, 1860.

 Events 
 Production of steel revolutionised by invention of the Bessemer process
 Benjamin Silliman fractionates petroleum by distillation for the first time
 First transatlantic telegraph cable laid
 First safety elevator installed by Elisha Otis
 Charles Darwin publishes The Origin of Species, putting forward the theory of evolution by natural selection
 Epidemiology begins when John Snow traces the source of an outbreak of cholera in London to a contaminated water pump.
 Discovery of Neandertal fossils in Neanderthal, Germany
 Solar flares discovered by Richard Christopher Carrington
 Crimean War (1854–1856) fought between Imperial Russia and an alliance consisting of the United Kingdom of Great Britain and Ireland, the Second French Empire, the Kingdom of Sardinia and the Ottoman Empire. The majority of the conflict takes place around Crimea, on the northern coasts of the Black Sea.
 The Indian Mutiny: revolt against the East India Company's British rule in India
 Dissolution of the Mughal Empire by the British.
 156 are killed in Paris in a failed assassination attempt on Napoleon III, Emperor of France
 Moldavia and Wallachia are unified and form Romania.
 Gideon T. Stewart attempts to create a Prohibition Party.

 World leaders 
 Emperor Franz Josef (Austria-Hungary)
 Emperor Napoleon III (Second French Empire)
 King Frederick William IV (Germany)
 Pope Pius IX
 Queen Maria II (Portugal)
 King Peter V (Portugal)
 Emperor Nicholas I (Russia)
 Emperor Alexander II (Russia)
 Queen Isabella II (Spain)
 Queen Victoria, (United Kingdom)
 Prime Minister Lord John Russell (United Kingdom)
 Prime Minister Lord Aberdeen (United Kingdom)
 Prime Minister Lord Palmerston (United Kingdom)
 President Millard Fillmore (United States)
 President Franklin Pierce (United States)
 President James Buchanan (United States)
 Nasser-al-Din Shah of Qajar dynasty (Persia)