ABSTRACT
In 1969, Thor Heyerdahl of Kon-Tiki fame undertook another perilous expedi-tion. Heyerdahl had noted a design similarity between boats on Lake Titicaca (Peru and Bolivia) and those depicted on tomb walls in Egypt. Theorizing that ancient Egyptians might have had some contact with the Americas, Heyerdahl attempted to sail from North Africa to South America in a papyrus reed boat.1 During the voyage of Ra I, the crew encountered areas of the ocean littered by lumps of tar large enough to pose a significant hazard to a small reed boat. The lumps had resulted from the then current practice of supertankers washing out their empty tanks in the open sea. The practice had seemed harmless because few believed that, given the breadth and depth of the oceans, such minor and sporadic episodes would cause permanent harm. This incident formed part of a global “wake-up call” that directed attention to the conservation of the global environment as an important issue.
