Toyota Prius Design Team

"We had to invent something completely original," says Satoshi Ogiso, executive chief engineer for Toyota's product-planning division. "We'd have to build it from scratch, blueprint and all."

Easier planned than done. Ogiso's 10-person team ultimately swelled to thousands (five of them, including Ogiso, center, are pictured here). The biggest challenge was the battery — too small and it would lack power, too large and it would overheat. In 1995, the first prototype ran for 330 ft. (100 m) before going dead...

Time: Heroes of the Environment