Did Ravana have 10 heads?

Once Ravana did stupendous penance to please Lord Shiva. Lord Shiva wanted to test the devotion of Ravana. He did not appear before Ravana. Ravana was so disappointed that he got ready to offer his life to Lord Shiva and he beheaded himself. Surprisingly another head appeared in the place of cut head. He repeatedly cut his head ten times where another head appeared constantly. At last Lord Shiva was so pleased with the devotion and sacrifise. Thus Ravana got a boon that no one can kill him by beheading. And also he got the knowledge of 6 ultimate sciences and 4 vedas. This is the actual symbolism of Ravanas ten heads. In reality he did not have ten heads but had the knowledge of ten heads.