The Crimson Valley is a location on Eternia that features in He-Man and the Masters of the Universe.
The Crimson Valley was a mountainous wasteland named after it's crimson colored appearance. The Chamber of Darkness where Darkdream had been imprisonned was located near the Crimson Valley.
When mysterious explosions caused by the dangerous mineral Nodroxyn weakened the seal on the Chamber of Darkness enough to allow Darkdream to use his nightmare powers once again, Prince Adam and Teela flew out to the Crimson Valley on Sky Sleds to investigate. Teela came under Darkdream's spell and fell asleep in mid flight. Luckilly He-Man appeared out of nowhere to rescue her, and left before she woke up. She was quite surprised when Adam claimed he was the one who had brought her to safety.