I'm trying to remove all .html files from the directory generated and from all subfolders there but it needs to leave all other files and directories alone.

I tried going through folder by folder and running rm *.html but this takes a long time as there are 20+ subfolders which also have subfolders. I tried looking the man pages for rm but nothing obvious jumped out. I'm sure there's a way to do this in one shot but I don't know how. Any ideas?