Gregor Mendel publishes his pea-plant hybridisation experiments in Brno; the work is widely recognised only after 1900.
James Clerk Maxwell publishes "A Dynamical Theory of the Electromagnetic Field", unifying electricity, magnetism and light.
France seizes Vĩnh Long, An Giang and Hà Tiên, completing the colony of French Cochinchina.
Marie Skłodowska-Curie, the first person to win Nobel Prizes in two different sciences, is born in Warsaw.
Dmitri Mendeleev arranges the chemical elements by atomic weight and properties, predicting elements not yet discovered.
The Nguyễn court cedes three eastern provinces of Cochinchina to France.
Vladimir Ilyich Ulyanov, later known as Lenin, leader of the October Revolution, is born in Simbirsk.