The essay should be 5-6 pages in length, font 11, double-spaced, and it should include properly formatted citations and a bibliography. I would suggest at least four sources.
This essay should not simply re-present the same material as your oral presentation. You’ll need to develop an interesting hypothesis, or approach that has meaning and relevance for you, your experiences or your field of study, that you can deal with the in the allotted length.
You might for instance compare the structure to a building that you know, or another structure we have visited in class, or write about a specific aspect of the structure or its history, or you may think of something entirely different to address. You may include pictures, although these should be counted outside of the required length.