Some folks travel to the world’s highest mountaintops. But Jim Malusa decided to do the opposite. Over a period of six years, Malusa biked his way to the lowest points on the face of the planet. A botanist, Malusa started in Australia and pedaled to what he calls “anti-summits” in Patagonia, Africa, as well as to Death Valley and the Dead Sea. Jim Malusa chronicles his adventures in the book, “Into Thick Air: Biking to the Bellybutton of Six Continents” and spoke with host Bruce Gellerman.