In 1906, a destructive earthquake hit the San Francisco area, causing enormous damage to the Stanford campus. I came across this interesting and very thorough site about the quake in relation to campus: http://quake06.stanford.edu/centennial/index.html.
There are a couple of extremely interesting parts of the site. First, the gallery of pictures of buildings shows us that, before the earthquake, a) some buildings we see today were different, b) some buildings were destroyed completely, c) and the layout of campus was not the same as it is now.
Differences: Memorial Church had a huge gothic spire and the front of the Quad had an enormous arch that needs to be seen to be believed. While the arch looks ludicrous to most of us, it had a very intricately carved frieze around the top that depicted the "Progress of Civilization in America." Destroyed: The Old Chem Building survived, but its neighbors the Gymnasium and the Library didn't make it. The architectural style of these buildings was much more classical than the Spanish style that prevails on campus. Layout: All of these buildings surrounded the Oval, indicating that the Oval was more of a campus hub than it is today. Also, original blueprints of the university (on this site as well) show that the original idea included two smaller quads directly adjacent to each side of the main quad.
Secondly, the gallery of pictures of people gives us more information about those involved in the quake. Two people died in the quake: a student in Encina Hall, the male dormitory (now home of the Political Science department) and the fireman, who went to cut power to campus to prevent a fire. Also, we can see all of the people who were involved in making decisions regarding the reconstruction of campus.
Lastly, there is a detailed walking tour that takes you through everything around campus through and after the earthquake. Check it out.