Flood protection from the mighty Mississippi river could be used as an example of a public good - it is very difficult to exclude any individual house or business from the benefits of building levees to stop floodwater reaching homes. The fairest way would seem to pay for this protection via the taxation system.
But the recent mega-flooding of the Mississippi in some areas has meant that the public defenses have been overwhelmed and any homeowners wanting protection have had to take matters in to their own hands, as the pictures below show. There was a fair amount of warning that the river would peak at a certain time so residents had time to undertake a cost-benefit analysis on whether it was worth trying to save their homes from the floodwaters. Unfortunately, not all of those who went to time and expense succeeded (see bottom picture).
The original article with more photos can be found here.