A traveler to the past can do a lot. If he doesn’t change the future, he can at least spy where treasures hidden away until the 21st century are located, uncover secrets of ancient civilizations, shed light on the greatest historical mysteries… And also save the other time-walkers who have gotten stuck in the past.
Is it dangerous? Oh, yes—extremely. In the past, almost everything is hostile; the chance of a safe return is minimal. But, thankfully, noble adventurers with spirit haven’t disappeared. There are still people like that!