When they retired, they hoped to winter in Florida.

Mostly, the microbiome is beneficial. It helps with digestion and enables people to extract a lot more calories from their food than would otherwise be possible. Research over the past few years, however, has implicated it in diseases from atherosclerosis to asthma to autism.

But where, through the development of trade or any other cause, a good many of them grew up close together within a narrow compass, they gradually coalesced into a kind of compound town; and with the greater population and greater wealth, there was naturally more elaborate and permanent fortification than that of the palisaded village.

Other areas have mortar joints missing, including between the voussoir blocks forming the edge of the arches on either side of the pier.