No, it is not possible to witness our past history by traveling at the speed of light or using any other known technology. According to the theory of relativity, the speed of light is an absolute cosmic speed limit. As an object with mass accelerates closer to the speed of light, its energy and momentum increase significantly, making it increasingly difficult to accelerate further. As a result, reaching or exceeding the speed of light is considered impossible for objects with mass.
Moreover, even if we could travel at the speed of light, it wouldn't enable us to witness events from the past. Time dilation is a fundamental concept in relativity, which states that time runs slower for objects moving relative to an observer. As an object approaches the speed of light, time dilation becomes more pronounced, and time effectively slows down for that object compared to a stationary observer. This means that from the perspective of a traveler approaching the speed of light, time would appear to pass more slowly, but they would still experience their own present.
Therefore, no matter how fast we travel, we cannot go back in time and directly witness events that have already occurred. The past is fixed and unchangeable, and our observations are limited to the information that has reached us through light or other signals from the past.