In the early 1900s Prokudin-Gorskii, a Russian photographer, developed an ingenious technique of taking colour photographs. The same object was captured in black and white on glass plate negatives, using red, green and blue filters. He then presented these images in colour in slide lectures using a light-projection system involving the same three filters. He went around what was Russian Empire then (1909-1915) and produced a series of amazing photographs.
In 1918, after the revolution, he fled from Russia, taking with him only his collection of nearly 2,000 glass-plate negatives and his photograph albums. The collection was purchased by the Library of Congress in 1948 from his heirs.
In 2001, the number of glass plates have been scanned and, through an innovative process known as digichromatography, brilliant colour images have been produced.
Here’s one of them and a link to some more restored by Alex Gridenko.