Many people use a variety of spiritual practices for this, and this is perhaps the most direct and effective method. The others are absorbed in the world of art, bizarre and wonderful, but still a man-made and therefore not fully alive. In its higher manifestations, this world is also capable to deduce beyond the limits.
But we can achieve this unity also by just letting the divine, which is spilled in the universe, go through us. Perceiving a lively and wonderful world around, not created by human beings. It is this natural way of filling the spirit which was always unknowingly used by simple man who lived on earth.
However, moving in line with the development of modern civilization, we rapidly lose it, the nature is becoming less and less accessible for the majority. The modern man no longer feels that he is a part of nature. His world is organized on some quite different, re-invented principles.But even in the artificial environment of modern cities nature is not completely destroyed. It grows in the most unexpected ways, sometimes only touching, and sometimes suddenly appearing in the urban world with some real living places having their own souls and characters. Do not confuse them with territories deliberately created by people, such as architectural ensembles or regular parks - these events are more probably related to art. The places I am talking about arise, as it were, by themselves, though not without human assistance. These are spontaneous breakthroughs of life in an artificial dead space. They exist in their own time and under their own laws. Just these mystical portals are instinctively or consciously being looked for and clung to as living sources, by unwitting prisoners of metropolis, who still retain a boundless thirst for another.