To get the full effect you would have to walk into Silent Valley from the Refinery side - through just about all of Little Aden the background sound is that of the Refinery, but when you enter Silent Valley you hear - silence! (especially on windless days)

If you went there before sunset, it was amazing, as the sun set the shadows grew up the mountain sides the heat dropped, then the katabatic wind gave a cooling breeze, and then darkness fell as if a light were switched off, and everyone moves instinctively towards the car. . . as it was dark, very very dark. Except on moonlit nights. A great place for seeing shooting stars.
Or boiling eggs in the sand during the day.

We had a similar thing when in Saudi Arabia on Tapline, the constant background noise was the marine Diesels and gas Turbines in the Pumphouse, so when you drove a couple of Km out of the station and stopped, you got pure golden silence

Email: gordon-clark@blueyonder.co.uk