TIME.com: Inventions of the Year -- The best inventions of 2001 "In rural northern Nigeria, there are no refrigerators. Most people don't even have electricity. So perishable food must be eaten immediately, or it will go to waste. Mohammed Bah Abba, a local teacher, has developed an ingenious solution: the Pot-in-Pot Preservation Cooling System. A small earthenware pot is placed inside a larger one, and the space between the two is filled with moist sand. The inner pot is filled with fruit, vegetables or soft drinks; a wet cloth covers the whole thing. As water in the sand evaporates through the surface of the outer pot, it carries heat, drawing it away from the inner core. Eggplants stay fresh for 27 days, instead of the usual three. Tomatoes and peppers last for up to three weeks. A recipient of the Rolex Award for Enterprise, Abba, 37, who hails from a family of potmakers, is using his $75,000 award to make the invention available throughout Nigeria. He has already sold 12,000." I've long thought that a cheaper, decentralized solution to refrigerators would make a big difference in Third World countries.