Silent Valley is called silent valley because of the absence of the Cicada the most common insect of the jungles and hence absence of their sound.
Silent Valley, Kerala
How to reach?
To Reach Silent Valley, Kerala, drive down from Coimbatore via RS Junction inside Coimbatore towards Anakatti and then Goolikadavu and then Mukkali and finally Silent Valley. Mukkali is where the Forest Office is.
Chennai -Salem= 350 kms (4 hrs to 7 hrs depending on max and min speed possible)
Salem-Coimbatore= 150 kms (3 hrs since the last 60 kms is a single road and so your speeds becomes slow on this stretch.)
Coimbatore- Goolikadavu= Takes 2 hrs. i.e. 60 kms.