title: Modeling RealEstate hierarchical location using MongoDB
body: <p>I am designing a Real Estate classifieds website. Each ad will have a location which will defined using the following three attributes (state, city, town).</p>
  
  <p>What's the best way to represent this in a Mongodb document? I am worrying about query performance because: </p>
  
  <ol>
  <li>Location will be the first search criteria </li>
  <li>I want to allow users to search by multiple locations.  </li>
  </ol>
  
  <p><strong>Example:</strong> A user looking to rent a flat in New York (state) or in Harrisburg (city in Pennsylvania).</p>