Ford's hot Fusion sedan is produced in a big factory in Hermosillo, Mexico -- and that factory has recently been working around the clock to keep up with demand. Photo credit: Ford Motor Co.

Investors have watched with great interest as Ford (F 0.37%)General Motors (GM -0.26%)Volkswagen (VWAGY -0.16%) and other big names have poured billions into new factories in China. But there's another auto boom happening a lot closer to home: All three of those giants, and several others, are pouring funds into new factories in Mexico as well.

Nearly 3 million new vehicles were built in Mexico last year, a number that could rise substantially in years to come. What's driving this auto boom? As Fool.com contributor John Rosevear explains in this video, Mexico's skilled, low-cost workforce -- and the North American Free Trade Agreement -- make the nation a great base for automakers looking to expand in the huge U.S. market.