What are the new heaven and the new earth? What will heaven be like for believers? Will the New Jerusalem be a giant cube?

What are the new heaven and the new earth? - https://www.gotquestions.org/new-heavens-earth.html

What is the New Jerusalem? - https://www.gotquestions.org/new-jerusalem.html

What is the eternal state of the believer? - https://www.gotquestions.org/eternal-state.html

What is heaven like? - https://www.gotquestions.org/heaven-like.html