In Chinese mythology, which mountain chain was believed to be a Taoist paradise?

The first to visit this paradise was, according to the legends, King Mu of the Zhou Dynasty. He supposedly discovered there the Jade Palace of the Yellow Emperor, the mythical originator of Chinese culture, and met Hsi Wang Mu, the 'Spirit Mother of the West', who was the object of an ancient religious cult which reached its peak in the Han Dynasty, and also had her mythical abode in these mountains.