(Qaaf) 50 : 7
وَالْأَرْضَ مَدَدْنَاهَا وَأَلْقَيْنَا فِيهَا رَوَاسِيَ وَأَنْبَتْنَا فِيهَا مِنْ كُلِّ زَوْجٍ بَهِيجٍ
And the earth, We have spread it wide, and We have set upon it mountains, and We have caused to bring forth in it every plant in beautiful pairs.
On the Day of Judgment, the setup of the universe at present will be completely altered into another form as explained in verse 14: 48. On that Day, mountains will become a cloud of dust, and the surface of the earth will become level, plain, and smooth just like a single marble is spread out as told in verses 20: 105-107. See explanation 22: 5; 51: 48; and 84: 3-5.