John Maynard Keynes:
If the Treasury were to fill old bottles with bank notes, bury them at suitable depths in disused coal mines which are then filled up with town rubbish, and leave them to private enterprise on the well-tried principles of laissez faire to dig them up again… there need be no more unemployment and, with the help of the repercussions, the real income of the community and its capital wealth also would probably become a great deal greater than it actually is.
These projects are, you will agree, at least better than burying bottles full of bank notes... as for hangars, zoos and ballparks, the WPA built them, too.