Place as character
The fundamental challenge of travel writing is giving a place the same specificity and presence you would give a human character. A character is not a type; a place is not a category. "A medieval city" is not writing. The cramped alley where the morning bread delivery arrives at 5 a.m. and the cobblestones are still dark with last night's rain — that is writing. A place becomes a character when it has mood, when it resists the traveler's assumptions, when it surprises. The writer's job is to find the particular details that make this place irreducible — the ones that could not describe anywhere else — and to build the place from those details outward.