Maybe somebody has an explanation for this experience:My wife and I were hiking on a trail called Oceanview Trail on Mount Tamalpais in Mill Valley, CA. The area has some Native American history, Gold Rush history and lumber history… it’s also home to Muir Woods National Monument. This particular trail travels along the ridge of the mountain and through redwood groves. It is absolutely beautiful. The fog rolls in extremely thick most nights there. It was near dusk and we were in a wooded area where the setting sun was breaking through the redwoods and foliage when I stopped to snap a couple photos (I had just bought a DSLR and was learning how to use it). My wife was about 20 feet behind me and nearer to the trailhead, heading back to our car. I snapped a couple of photos (trying to catch the sun rays peeking through the forest) and put my camera away. That was when it happened, all within the span of about ten seconds. I heard a twig snap and looked up and because of how I had positioned myself for the shot the sun was directly in my eyes. A whirling echoing breathy whistle filled my ears like my head was inside an echo chamber. There’s no other way to describe it other than it felt like it surrounded my head. Three whistles. The first two quick and the third long and trailed off. The feeling and the sound (along with the sunlight) sort of overwhelmed my senses for that instant and all I could do was rapidly blink. In the flash of one those blinks was a big bulking silhouette seemingly five feet in front of me, gone as quick as it was there. I took a half step back and it was all over. I was a little shaken but mostly confused. When I turned around my wife was facing me, slightly confused and frightened- half by how out of it I was and half by what she had heard. She asked if I was okay and I said, “We should go, now.” We fast walked the rest of the way to the car looking back over our shoulders but nothing else happened. The trail looked just as pleasant as before the incident. In the car my wife described what she had heard. She described it as hearing a twig snap and what she thought was either a long whistle or whiny childlike scream but slightly distant-sounding. She said it caught her attention because it didn’t sound human but more like an animal. It felt surreal and otherworldly. I felt this electric buzz for the next 10-15min. We drove to the other side of the mountain to wait for the fog to roll in and maybe get more photos but after recalling our story over and over again decided it was best to leave. Two closing points: 1. No, nothing mysterious showed up in my photos and 2. Yes, the area has had 2 documented reports of Sasquatch sightings (though I don’t consider this to be necessarily related in anyway). Just wondering if anybody out there has had a similar experience or if this sounds like some known phenomenon. I haven’t come to any conclusion, just interested to hear what others have to say. The best explanation I’ve received is possible infra-sound.