Library of Congress Card Catalog

AtlasObscura:

In the ’80s the LC removed the wooden card cabinets from their spot of honor in the Reading Room and brought in personal computers. The catalog was first brought onto the World Wide Web in 1993. The webpage wasn’t as sexy as the old card system, but it was far more accessible to the American public. Today it is queried millions of times per day. Bizarre side note: The online catalog website actually had operating hours when it was first launched and “closed” at 5 p.m. Pulitzer Prize-winning Washington Post reporter Margot Williams warned her readers in 1994 “don’t try this [accessing the website] at midnight.”