I'm trying to understand how to optimize landing pages to appear in local search. For example, if someone in Chicago searches for "plumber", Yelp has a page "Top 10 Plumbers in Chicago." They are generating these pages for numerous business types and cities. I can't see anything on the page or metadata that indicates a geographic location or business type. What optimizations are they doing to get Google to know that it's a page for a specific city and type of business?