A city and a tower] The principal building in every ancient city was its temple, and the chief feature of a Babylonian temple was its ziggurat or stage-tower. The remains of these towers are the most prominent of the mounds which mark the sites of ruined cities. The pile of vitrified brick near Babylon, known as Birs Nimrûd, is the best known example of such a ziggurat, and early travellers supposed it to be the biblical Tower of Babel. The most famous temple-tower, however, and the one which probably gave rise to the tradition here, was that of E-Sagila, the temple of Bel in Babylon, built of brick in seven stages, the topmost of which formed a shrine for the god. It was of extreme antiquity, and was restored and beautified by Nebuchadnezzar.
Whose top may reach unto heaven] cp. Deuteronomy 1:28. The expression 'Whose top is in the heavens' has been found on inscriptions concerning these storied towers, but it seems as if the writer regarded the enterprise as an impious attempt to scale heaven. Let us make us a name, etc.] The tower was meant to procure renown for its builders, and to serve as a centre and bond of unity, so that none would think of leaving it. The writer seems to indicate the intention of establishing a universal empire.
These are the generations of the heavens and of the earth when they were created] i.e. this is the history of their creation. See on Genesis 1:1-3. The phrase 'These are the generations' occurs ten times in Genesis, viz. Genesis 2:4; Genesis 5:1; Genesis 6:9; Genesis 10:1; Genesis 11:10; Genesis 11:27; Genesis 25:12; Genesis 25:19; Genesis 36:1; Genesis 37:2.