Most of these rooms hold one region. This one holds a river — and the river doesn’t care about city limits. It starts in the drowned edge of the Gulf and runs north through the whole middle of the country, and everything living on it (barges, storms, and one very determined fish) is trying to get somewhere along it. Read it the hard way: from the mouth, upstream, to the last gate.
In 1927 the Mississippi flooded seven states, and the Army Corps admitted the only way to understand the river was to build the whole thing — 200 acres of concrete near Jackson, every tributary in miniature, water run through it for twenty-four years. You can’t hold the river whole in one head, so you build a model and walk it. This corridor is that model: four rooms strung on one current, so you can walk the Mississippi at a scale that fits.
South to north, mouth to gate — the derricks, the barges, the crossing, and the carp. One river, four rooms, one current pulling all of it the same direction. More of the corridor slots in as the stories deploy.