John Berger, Opening a gate
In my opinion, Berger is giving an advice to the reader, a sort guideline for life. You need to take your time and look closer, basically you need to make a step further. Open a gate in your mind and step over the 'border' to a new way of perception. People of nowadays time are so stuck in their daily routine and tend to be stressed out. In this frenetic world, they walk straight ahead without spending any time to the beautiful and surprising things you can see when you give yourself some time and rest. Be open for another visible order and don't just stick to your old and customary courses. There is so much more to see and experience when you live your life as an attentive observer.