In Bedford-Stuyvesant, a hotbed of New York gentrification, half-a-dozen unusual billboards have popped up since August, Colorlines reports.

What makes them different from the usual bus-stop advertisements? For one, they're not selling anything but a declaration: that racism still exists, in areas from policing to education. Then there's the fact that no one knows exactly who's behind them. If the creator's goal was to start a conversation, the effort has been a success:

So far, the billboards have touched on topics ranging from the entertainment industry, education, fast food, smoking, policing, and black wealth. Each month's billboard is also accompanied by an detailed post on Tumblr that provides background information, news articles, studies, charts, and statistics to back up each claim.  

A brief statement on the Tumblr page says, in part, that "RISE is a [project] designed to illuminate some of the ways in which racism operates in this country." But who's behind the project remains a mystery.

Billboards are everywhere in New York City. They're on subway trains and in stations, and on top of and inside taxis. But few, if any, have been anything like a series of anonymous billboards that have popped up on bus shelters in the Bedford-Stuyvesant neighborhood of Brooklyn …

For the time being, the project seems dedicated to its anonymity. Both the Tumblr page and the billboards themselves are devoid of any contact information. Similarly, the private advertising company that's contracted by New York City's transit agency to host advertisments and billboards said that it does not give out information about who paid for the advertisements. 

Read more at Colorlines.