I'll assume we're sticking strictly to moving back in time, and not forward. In this case, there is an incredibly long list of where and when in time I'd like to visit. In particular, I'd be interested in spending a lot of time within the 16th and 17th centuries. The opportunity to sit down with Newton, Leibniz, Galilei, Kepler, and Brahe would be not only extraordinary, but nothing short of inspiring for an individual who takes a love in the sciences; whom is habitually inquisitive with a determination to learn. However, due to my gender, my rights would be extremely limited even in such a recent century. Due to this set back, I'd be more than happy to travel further back, as I couldn't pass up the chance to observe, first hand, the evolution of early hominids and other creatures from prehistoric time. Even the ability to test and study the environment and life forms present in prehistoric time would provide huge benefits to modern science and our understanding of the world.