Height of the tower
The Book of Genesis does not mention how tall the tower was. The phrase used to describe the tower, “its top in the sky” (v.4), was an idiom for impressive height; rather than implying arrogance this was simply a cliché for height. The tower’s height is discussed in various extra-canonical sources.
The Book of Jubilees mentions the tower’s height as being 5,433 cubits and 2 palms, or 2,484 m (8,150 ft), about three times the height of Burj Khalifa, or roughly 1.6 miles high. The Third Apocalypse of Baruch mentions that the ‘tower of strife’ reached a height of 463 cubits, or 211.8 m (695 ft), taller than any structure built in human history until the construction of the Eiffel Tower in 1889, which is 324 m (1,063 ft) in height.
Gregory of Tours (I, 6) writing c. 594, quotes the earlier historian Orosius (c. 417) as saying the tower was “laid out foursquare on a very level plain. Its wall, made of baked brick cemented with pitch, is fifty cubits wide, two hundred high, and four hundred and seventy stades in circumference. A stade contains five agripennes. Twenty-five gates are situated on each side, which make in all one hundred. The doors of these gates, which are of wonderful size, are cast in bronze. The same historian Orosius tells many other tales of this city, and says: ‘Although such was the glory of its building still it was conquered and destroyed.'”
A typical medieval account is given by Giovanni Villani (1300): He relates that “it measured eighty miles round, and it was already 4,000 paces high, or 5.92 km (3.68 mi) and 1,000 paces thick, and each pace is three of our feet.” The 14th-century traveler John Mandeville also included an account of the tower and reported that its height had been 64 furlongs, or 13 km (8 mi), according to the local inhabitants.
The 17th-century historian Verstegan provides yet another figure – quoting Isidore, he says that the tower was 5,164 paces high, or 7.6 km (4.7 mi), and quoting Josephus that the tower was wider than it was high, more like a mountain than a tower. He also quotes unnamed authors who say that the spiral path was so wide that it contained lodgings for workers and animals, and other authors who claim that the path was wide enough to have fields for growing grain for the animals used in the construction.
In his book, Structures or why things don’t fall down (Pelican 1978–1984), Professor J.E. Gordon considers the height of the Tower of Babel. He wrote, ‘brick and stone weigh about 120 lb per cubic foot (2,000 kg per cubic metre) and the crushing strength of these materials is generally rather better than 6,000 lbf per square inch or 40 megapascals.Elementary arithmetic shows that a tower with parallel walls could have been built to a height of 2.1 km (1.3 mi) before the bricks at the bottom were crushed. However, by making the walls taper towards the top they … could well have been built to a height where the men of Shinnar would run short of oxygen and had difficulty in breathing before the brick walls crushed beneath their own dead weight.”