Marathons

From Barcelona to Boston and New York: the marathon is a runners supreme test. Here are 42 standouts, complete with practical information: when theyre run, how to register, how to train, how difficult each is; and which courses are hottest, coldest, and most spectacular. Some exotic choices include the high-altitude Kilimanjaro Marathon, Beijings Great Wall Marathon, and the Flying Tortoise on the Galapagos.