Imagine you come across a time machine and that with this machine time travel is possible, however, you can only make one round trip to the past and back. What year would you travel to and why?

It would be tempting to go back in time to attempt to change or experience any number of events throughout history but I would not use the machine. I am afraid that any change to the past, no matter how small, could have unknown repercussions that spread through time and change the world as I know it, threatening those that I know and love and even my own existence.