Although I have a PhD in neuroscience and worked in research for 11 years, since 2008 I have been only involved in geographic exploratory pursuits related to rivers.  In particular, my goal is to document, publicize and protect the rivers that flow through the Grand Canyons of the world, most of which are targets for building hydroelectric dams. I’ve been the first person to research, paddle, and document  >100 rivers in the world, mostly in Mexico and Latin America, but also several in Myanmar and Ethiopia.  In 2012, I discovered the most distant source of the Amazon, led expeditions to the source and also to paddle the entire new source stream (the Mantaro), and compare directly the distance measured with GPS to the formerly considered most distant headwater stream (the Apurimac).  I wrote up and published these results in the journal AREA (see https://rgs-ibg.onlinelibrary.wiley.com/doi/abs/10.1111/area.12069#support-information-section). I then continued down the rest of the Ene-Tambo-Ucayali-Amazon to become the first person to complete the descent of the entire Amazon from source-to-sea.  Part of my recent efforts have focused on a complete description and descents of the second and third longest rivers in the world: the Nile and Yangtze.  I continue in my efforts to explore, publicize, and protect the threatened and unique Grand Canyons of the world, and have been focusing attention in the past several years on the deepest canyons of each continent.  My main job these days involves organizing rafting expeditions to these rivers that anyone can join and I invite other members to become part of these expeditions (see more info at www.SierraRios.org).