One day we and everyone who knew, know and will know us will die. Not only there won’t be any physical trace anymore of us but also any memory. Then, the sun will blow up and each form of live will die on our earth. Even if there are other civilisations, it will happen to them too one day. It means that there won’t be any observer who is needed for the concept of reality. So, one day the reality as concept won’t exist anymore.