The new heavens and earth will look like this world but without sin. Imagine how the world would have looked if Adam and Eve had not fallen in the garden. I fully expect mountains, rivers, oceans, animals, and so on, but without sin.
It is very difficult for us to imagine what sinlessness and the possibility of not being able to sin actually looks like. We have never experienced that, not even in our regenerated, Christian lives because we are still capable of sinning.
The new heavens and earth will be beautiful and glorious. They will be filled with a sense of the glory of Christ. It will be a wonderful, family-like experience, and I can’t wait.