As for that amusing piece of fan fiction ranking the tallest buildings on Earth, in which the Burj Khalifa in Dubai falls slightly short of the tower of Barad-dûr in Mordor, let me remind you that this is nothing more than conjecture: nowhere in the text
And if, like the author of this infographic, you are working from the visual impressions of Peter Jackson's film adaptation, then one must not forget the Tower of Ecthelion on the uppermost tier of Minas Tirith, or Orthanc, for instance.
Still, the comparison of the aesthetics of the Arab sheikhs and of Sauron has a charm of its own.