The Earth has been visited, watched and studied for a very long time. These visitations have been from a number of different races for different purposes.
But your past experiences cannot really help you now. Visitation was extremely infrequent, and what is known has become so changed that it holds no accurate or direct record of intervention or foreign presence in the world.
Today, you have allies in the universe though they are not visiting your world, for humanity is not ready to establish relations with other nations in the universe. Your allies abroad only seek to alert you to the presence of extraterrestrial races interfering in human affairs and to teach you some vital and important things about life in the universe around you.