This photo was taken during a recent visit to the Marin Headlands, just across the Golden Gate Bridge from San Francisco. This is a park and recreation area that is full of old World War II defense structures that are now in various states of disrepair. The ruins made for extremely inspiring photography.
I love seeing old building like this and try and think about what it was intended for when it was built and comparing it to what it is being used for today. You can find some great picture opportunities in places like this.