Invisible?

Last semester I was abroad in Australia and while I was abroad I took several thousand pictures. For my first post I decided to look through all of my pictures to see if any of them had any trash pictured in them. I found none, instead a large number of them had trash/recycling cans in the background. While most of my pictures were of wildlife or natural landscapes well away from much human contact. I would say that most of the pictures taken in cities or towns had trash or recycling cans in them. Above are two such pictures, the first is a shot of Manly Beach which is a well known beach outside of Sydney. The other is a shot of the Opera house taken from the botanical gardens. What is most interesting about these shots is that the pictures are not of the trash cans, however because trash is such a part of modern/urban life I didn't even notice them as I was taking the picture. The trash cans were invisible to me. When I realized this I went back and counted all of the trash cans in total I have 20 trash cans in all of my study abroad photos.