10 walking tour ideas

Places where authors lived and/or places mentioned in books, etc.

Comedy clubs, scenes from funny movies etc.

Deaths, sites of tragedies etc

Philosophers, writers and whatnot. Where they lived, worked, socialized, etc.

Russian culture tour of Brooklyn, Jewish culture tour of Paris, Persian tour of LA, etc.

Conservative tour (where conservative icons lived, sites of politically conservative events, etc.) or the equivalent for left-wing or liberal politics.

Some sort of quest, a treasure hunt, or something. Maybe each participant ends up in different places depending on the clues they find.