Provided I had a good compliment of arms I would love to travel back about 40,000 years to North America where more animals habitated on our great plains than in Africa.
If I could change history, I'd go back to the area known as San Salvador in 1491 and give the native folk there a bevy of heavy munitions.
Otherwise, I would love to Karakorum as an emissary from the future to Genghis Khan and his court.
I would also love to meet the mythic Lao Tzu, if there was one.
I would travel back to the height of the Mughal Empire in 1570s to be a guest in Akbar's court.
Meet Jesus of course and see what the real story was with him and the mysterious undocumented period in his life.