For most of us, traveling means visiting the most beautiful places on Earth--Paris, the Taj Mahal, the Grand Canyon. It's rare to book a plane ticket to visit the lifeless moonscape of Canada's oil sand strip mines, or to seek out the Chinese city of Linfen, legendary as the most polluted in the world. But in "Visit Sunny Chernobyl," Andrew Blackwell embraces a different kind of travel, taking a jaunt through the most gruesomely polluted places on...