Description
The Rotterdam painting is about half the size of the Vienna one. In broad terms they have exactly the same composition, but at a detailed level everything is different, whether in the architecture of the tower or in the sky and the landscape around the tower. The Vienna version has a group in the foreground, with the main figure presumably Nimrod, who was believed to have ordered the construction of the tower, although the Bible does not actually say this. In Vienna the tower rises at the edge of a large city, but the Rotterdam tower is in open countryside.
The paintings depict the construction of the Tower of Babel, which, according to the Book of Genesis in the Bible, was built by a unified, monolingual humanity as a mark of their achievement and to prevent them from scattering: “Then they said, ‘Come, let us build ourselves a city, and a tower with its top in the heavens, and let us make a name for ourselves; otherwise we shall be scattered abroad upon the face of the whole earth.'” (Genesis 11:4).
Bibliography
The Tower of Babel (Bruegel), https://en.wikipedia.org/w/index.php?title=The_Tower_of_Babel_(Bruegel)&oldid=1096899915 (last visited Aug. 10, 2022).