These are usually one day affairs and are typically based on a running race of 3-12 miles, but those miles are fraught with hazards not found on any normal marathon or half-marathon course, from mud pits to vertical walls, fiery flame barriers to electric shocks, ice plunges to crawls under barbwire.

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Not to be outdone, England just flipped the switch on the world's largest wind farm, and in Paris, Schneider Electric set up kinetic energy-harvesting tiles that generate power from runners in the Paris Marathon.

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