At the top of the stairs! Beautiful saguaros, some of which were pretty sizeable. Someone on the tour asked if they had been planted, and the ranger said no-- saguaros tend to grow mainly on the slopes of ridges so as to catch as much moisture as possible, the runoff as well as the direct fall of rain. These grew where their seeds had fallen in nature-- saguaros on utterly flat ground aren't as common, though they definitely occur.