Orbs in San Francisco

I took some pictures of the Golden Gate and The Rock (Alcatraz Island) and what was my surprise when I noticed there were many orbs in there. I mean, that's a place where much have happened, but that there were so many of what I personally call "orbiting round-bounded spirits" all around the area, that's huge. See it for yourself (Click on the pics to see bigger trails with more details:)
Some would say that's just the effect that digital cameras sometimes expose, I give the benefit of doubt, the one I used was brand-new, I just had bought it there. And if it was the case of water spots or dust on the lens, I would not have normal photos in a sequence of photos from the same camera and location as I had shown up here. All of the shots in this sequence should have the dust or the fog in it. The orbs did not appear in consecutive photos, some had them and some just didn't. And period. Case closed. For there is more on earth and heaven than even the most trained eye couldn't explain. And if there is something that catches my attention are those circles that appear to float, hovering over some particular areas where seem to derive an eerie atmosphere.
More photos with orbs on my site:
http://www.geocities.com/AnnaClaudiaAntunes/Orbes.htm