Ancient Egypt
Three thousand years of one country, kept together by a river that floods on schedule. Egypt is the state that other ancient states are measured against — the earliest with a bureaucracy, a surveyed tax base and a settled idea of what a king was for — and it broke apart and reassembled on roughly the same ground more than once.
The line below is a time axis. Position on it is date, so concurrency is visible: concurrent polities sit side by side rather than in sequence.
5 sourced edges run between this region and another, to Kingdom of Kush, Neo-Assyrian Empire and Achaemenid Empire. Those are not drawn on this line — a thread that crossed regions would assert a sequence nobody cited — but they are on each polity’s own page.