Nostalgia is a link to what Wikipedia looked like back in 2001 when we had only 19,000 articles.
The English Wikipedia now has over 6,908,723 articles. (purge server to refresh number). The five-millionth article, Persoonia terminalis, about a rare shrub, was written by an editor in Australia just after midnight on November 1, 2015.
To view an archived version of Wikipedia between 2001 and now, see the Wayback Machine.