Essays / How to write a descriptive essay about a city (Rome)? How to organize the essay? [2]

I am a university student of English and one of my assignments requires me to write an essay on the topic Discovering...(a city/country/town).

So, my topic is Discovering Rome.

I think this topic falls under the category of descriptive essays, but I don't understand in which order I should describe the city (the spatial order). Can somebody please help?

The word limit is 600-750