Three Gates

The concept. None of these cities got rich making things. Each stood where something had to stop and charged for the crossing: the gap where the water ran out and cargo had to be carried, the only break in the mountain wall that a boat could use, the closest American ground to money leaving a hemisphere. No publisher would run the numbers on that comparison, so it was built for one reader who has lived in two of the three and is going to see the third.

How it was built. Every factual sentence traces to a source, and every source was graded. A claim is only as good as its worst source rather than its best, and four sources agreeing because they copied each other count as one, which is why several widely repeated claims are reported as resting on nothing.

What it traces. How each gate was built, what it cost, who paid, and what it became. Then who took an idea from whom, sorted into documented, inferred, and undocumented. Where a parallel does not exist it is reported as missing, since Miami never had a commodity exchange, and the absence is usually the more interesting finding.

It will not tell you what a city feels like. It tells you what kind of machine each of the three is, and whether all three are the same kind of machine, which is what the comparison turns on.