I'd really like to know that too. Also, are they collecting data themselves? If not, where are they getting it from?
Another impressive spot is the top of the Stratosphere Tower in Las Vegas -- it manages to capture the spike at the top fairly well. It'd be interesting to know how much hand-editing they did for sites of interest like that, and how they represent hand-edits in a way that can be re-applied when new lidar datasets come in.