This chapter begins with a visit to Manaus, once the rubber capital of the world. Entangled long molecular chains that stretch, deform, and reform made a material that was an important part of Maya political, religious, and social life well before the apogee of the rubber boom in Brazil. Rubber became a commercially important material when a technique was developed to permanently link the chains using heat and sulfur in a process called “vulcanization.” Vulcanized rubber became essential for tires in the rapidly growing automobile industry following the introduction of the Model T Ford. The material was so important for the war effort that President Franklin Roosevelt declared it a “strategic and critical material.”