Opened January 2010. Named after Sheikh Khalifa bin Zayed of Abu Dhabi, after Abu Dhabi's financial support rescued Dubai during the 2009 debt crisis — which explains why the name changed from Burj Dubai at the last moment.

No photograph, no video, no description prepares you for the scale at street level. The observation deck at level 124 is the tourist option; At The Top SKY at level 148 is the one where the glass floor stops being funny. The Dubai Fountain below it at sunset is better than it sounds. The queues are not.