Quartz:

Just call 917-ASK-NYPL, and a live librarian will try to answer your question, using vast archives collected over 120 years.

And:

Set up in the 1960s, the line is manned by nine librarians and information assistants. The team gets a lot of calls from people who want to fact-check things they’ve heard on the news, says Caballero-Li.

What I find amazing is that this service still exists, has not been overwhelmed with demand. Fascinating read.