The new heavens and new earth, as mentioned in Revelation chapters 21 and 22 and in 2nd Peter 3:10-13, were created by God at the end of the Millennial Reign, following the Great White Throne judgment in "Kingdom Come", when the old earth was destroyed.
Doctrines concerning the "new heavens and new earth"
Opinions as to how God will bring about the "new heavens and new earth" vary among Bible eschatology students who interpret the book of Revelation according to the futurist interpretation. Some people believe that God will completely annihilate both the heavens and the earth and recreate them from scratch (as implied in 2nd Peter 3:10-13 in some translations like the King James Version), while others believe that God will just burn up everything that is on the earth while leaving the earth itself (its very foundation) and the heavens intact. The authors of the Left Behind books chose to depict this as simply the old earth being destroyed and a new earth being created instantaneously afterward.