If we want to provide a comparison, we can say that this is like a traveler or a caravan that is passing through difficult twists and turns, rough passages, mountains, valleys, swamps, and scrublands in order to reach a specific point. Where is this point of destination exactly? This point is a freeway, a major road, and an open, smooth path.
All the things that we've witnessed throughout the history of humanity are movements on these very same difficult paths, with the same twists and turns, in the same scrublands and swamps, and the like. Humanity is constantly taking this path in order to reach such a freeway. This freeway is the era of Mahdaviat: it is the era of the re-appearance of Hazrat Mahdi (God's greetings be upon him).
However, it is not the case that when we reach this freeway, a sudden movement is launched, and then it comes to an end. This one point opens up to another path. In fact, it should be said that humanity's primary and ideal life begins from that point, and humanity has just begun to take a straight path which helps it reach the final destination of creation.
Imam Khamenei, Jun 11, 2014