Years ago, I saw a time traveling movie, in the movie people go back hundreds of thousands of years, there are aliens involved, I think they can see into the past at one point on some kind of screen. The aliens were in the past on earth doing something or other. I think the movie was titled something like 20,000,000 years something or other. Its at least thirty years old.
Could it be Journey to the Center of Time? According to Wikipedia it involves time travel to both the future and the prehistoric past, aliens trying to colonize the Earth. The full movie is on DailyMotion, the scene from about 8:00-9:00 shows they do have a giant screen which they can set to show past times:
Also, this movie was a remake of the earlier movie The Time Travelers, although that one didn't feature aliens or a trip to the past.