כָּל־אֵ֜לֶּה עָרִ֧ים בְּצֻר֛וֹת חוֹמָ֥ה גְבֹהָ֖ה דְּלָתַ֣יִם וּבְרִ֑יחַ לְבַ֛ד מֵעָרֵ֥י הַפְּרָזִ֖י הַרְבֵּ֥ה מְאֹֽד׃
All these were fortified cities, with high walls, gates, and bars; beside the unwalled towns a great many.
Read midrashic interpretation of Deuteronomy 3:5: and classical rabbinic exegesis.