But what does that mean?
Here's their release on the topic:
Mellon Foundation Announces Quarter-Billion-Dollar Grant Commitment for “Monuments Project” to Reimagine and Rebuild Commemorative Spaces and Transform the Way History is Told in the United States | The Andrew W. Mellon Foundation: A press release from The Andrew W. Mellon Foundation.
And yet I still don't know what that means.
I do know that $250,000,000 is a lot of money. But is it a lot of money in this context. That depends, I suppose. But it'd depend on things that aren't clear, and its not clear what they really mean.