Stone Town Zanzibar is a very busy and seemingly disorganized town with many little narrow streets and alleyways.
Cars just drive around the edges and you walk into the warrens and pathways. We were assured it was safe and we never felt that it wasn't.
We did a small tour which covered the Cathedral and the old slave chambers plus the markets and the "house of wonders" or the national museum.
All were quite interesting and well worth the time.
It was also quite nice to just walk around and see the architecture and wander the alleys and get lost and see where you would wind up.