Got any more information about "Manhattan burned to the ground"? I can only find two "great fires" that may be relevant, and neither of them gave Manhattan a do-over.
The Commissioner's plan is the reason Manhattan has a grid system, and the page for it doesn't reference any fires.
https://en.wikipedia.org/wiki/Commissioners%27_Plan_of_1811
Finally, the streets before the Commissioner's plan took effect are still rather small and twisty.