Jason Kottke is going archive crazy with the New York Times. The Times dropped the paywall that locked non-subscribers out of its archives last week, and at the time, they noted that they hoped that this would inspire bloggers and others to go mining through the incredibly rich corpus of news and stories stretching back through the past two centuries. Kottke's certainly turned up some gems, but there's plenty more to be had — post your finds in the comments!
– The first mention of the World Wide Web in the Times in February 1993. According to the article, the purpose of the web is "[to make] available physicists' research from many locations". Also notable are this John Markoff article on the internet being overwhelmed by heavy traffic and growth…in 1993, and a piece, also by Markoff, on the Mosaic web browser.
– Early report of Lincoln's assassination…"The President Still Alive at Last Accounts".
– A report on Custer's Last Stand a couple of weeks after the occurance (I couldn't find anything sooner). The coverage of Native Americans is notable for the racism, both thinly veiled and overt, displayed in the writing, e.g. a story from September 1872 titled The Hostile Savages.
– From the first year of publication, a listing of the principle events of 1851.
– An article about the confirmation of Einstein's theory of gravity by a 1919 expedition led by Arthur Eddington to measure the bending of starlight by the sun during an eclipse.
See also: NYTimes kills its paywall: "Google visitors make more dough than subscribers"