Ten Days in a Mad-House (1887)

I found three small previous threads. Others?

2016: https://news.ycombinator.com/item?id=10926253

2015 (a bit more): https://news.ycombinator.com/item?id=10470383

2014: https://news.ycombinator.com/item?id=7730311

Nellie Bly pretty much invented investigative journalism. Even today her journalistic investigations are fascinating.