Finding a row and columns in your nav div is unexpected. I'm not sure how that happened, but they will have to go.
inside your neighborhood-guides div is also unexpected, and also will have to go.
After that things look pretty good. There is still a bit of mix up in the neighborhood-guides columns. After the first column you have three
</div> tags. One closes the thumbnail -- that's good, one closes the column -- also good, and one closes the row -- that's bad. You don't want to close your row until after the third and final column is closes.
Let me know how you get on with that.
How to post code in this forum.