Hart Island, Anon..should be a big eye opener for them…
Unearthing the Secrets of New York’s Mass Graves
https://www.nytimes.com/interactive/2016/05/15/nyregion/new-york-mass-graves-hart-island.html
Dead of Aids and Forgotten Potter Field
https://www.nytimes.com/2018/07/03/nyregion/hart-island-aids-new-york.html
You just need to find the thing that is close enough to them to make them ask moar questions. Don't preach..just subtle questions..and let them think on it.