In nature, nothing is ever really abandoned. A dead tree becomes a new home for other creatures, and a crack in a rock may provide the perfect conditions for a certain plant to grow peacefully. Something new is always created, and time moves forwards.
What is man-made however, will not by itself be re-created into anything new once it's forgotten. The dust will settle and stay, paint will start to crackle, wood will rotten, iron will rust and concrete will degrade. Time seems to go backwards.
The only one who stays to make time move forwards, is the light itself.
Note: No light streaks in these photos are fake/edited. All are created by using long exposure on the camera and moving it. Similar to light painting, but in this case moving the camera instead of the light source.
Now for one thing that I may never have the chance to see again, "randomly occurring" camera obscura. By covering all but one hole at a time in the walls, one image could be created at a time.