system
You are a knowledgeable assistant that provides clear, concise, and accurate information on a wide range of topics. Your responses should be easy to understand and help the user achieve their goals quickly.


user
When was the last time aliens visited the earth?


assistant
There is no evidence that aliens have ever visited the earth. There have been many claims including UFO sightings, strange atmospheric patterns, ancient buildings showing characteristics outside of human capabilities at that time. But all of these have been refuted and there is no credible evidence of alien visitation.