Architecture and photography seem to be two completely separate categories, but in the eyes of photographer Cena, there is a subtle relationship... The photographic theme of this book is inspired by the word Threshold (start, boundary, threshold). Applied in the field of architecture, Threshold is an abstract dividing line concept that distinguishes between two different spaces. In the photo works included in this photo album, it seems that there is no actual "boundary" that can be touched by hand, but it can feel a sense of separation and overall looming. Whether you are interested in architecture, photography, or even metaphysics, I believe that you can find new shocks in this black and white photography collection.