If you are interested to know Giant factory, at this link is possible watch some pictures from visit by the Italian MTB forum.
At Taichung village in Taiwan, Giant have the largest manufacturer of bicycles in the world. With 5,200,000 frames produced in 2011, of which 3,000,000 for its brand and the rest for other companies, Giant billin in the 2010 1.39 USD billion.
The company was founded in 1972, when it produced 3,700frames. The Giant name was created in 1981, and in 1987 came from the factory the first carbon bike brand. Now Giant has 9 factories in Taiwan (the object of Italian MTB forum visit), China and other countries including the Netherlands, where there is an assembly line and paint. Worldwide there are 11,125 stores that sell Giant, scattered among 80 countries. The strongest markets are Europe, where Giant gets 30% of turnover, the U.S. with 23%, China with 24% and Japan with 10%.