Giant cacti in Arizona

Arrived in Dove Mountain (north of Tucson in Arizona) for Techonomy12 conference at the Ritz Carlton hotel. I elected to do a guided mountain-bike ride after I arrived and it was such an amazing experience. The track was interesting with some technical descends and sand patches. The sun was setting in an orange glow and the air had a sharp, cold bite, but it was the vegetation that was the most spectacular. These huge cacti was everywhere also with a wide variety of other cacti and trees.