Nebraska becomes the 37th U.S. state, carved from the Great Plains territory acquired decades earlier through the Louisiana Purchase.

U.S. Secretary of State William Seward signed a treaty buying Alaska from Russia for $7.2 million, a deal mocked at the time as 'Seward's Folly.'

Secretary of State William Seward signed a treaty purchasing Alaska from Russia for $7.2 million, a deal mocked at the time as 'Seward's Folly.'

Karl Marx published the first volume of 'Das Kapital' in Hamburg, a dense economic critique of capitalism that would shape the 20th century's ideological battles.

The Second Treaty of London confirmed Luxembourg's independence and perpetual neutrality, defusing a crisis that had nearly triggered war between France and Prussia.

The British North America Act took effect, uniting Ontario, Quebec, Nova Scotia, and New Brunswick into the Dominion of Canada.

The British North America Act took effect, uniting Ontario, Quebec, Nova Scotia, and New Brunswick into the Dominion of Canada.

The British North America Act took effect, uniting the provinces of Ontario, Quebec, Nova Scotia, and New Brunswick into the Dominion of Canada.

Russia formally transferred Alaska to the United States at Sitka, ending 126 years of Russian colonial presence in North America.

Maria Skłodowska was born in Warsaw, later becoming the first person to win Nobel Prizes in two different sciences.

Samurai reformer Sakamoto Ryoma, architect of the alliance that ended Japan's shogunate, was assassinated in Kyoto weeks before the Meiji Restoration.

Orville Wright, who with his brother Wilbur achieved the first powered, sustained flight of a heavier-than-air aircraft, was born in Dayton, Ohio.