Help -

I have built a relatively simple environment, but noticed that the some of the vertices are not connected to each other (I used Extrude Face mainly). I tried using the Merge Vertices tool as well as the Merge Edges tool; however, they do not merge together. I even adjusted the settings. Still nothing.

Any ideas?

Also, if building a simple environment/architectural scene should it consist of one continuous object?

Thanks,
Brandon