Makkah clock tower or Zam zam tower is the 2nd tallest building in the world after Burj Al-Khalifah in Dubai. Makkah Tower is situated in front of Holy Kaaba In Holy City of Makkah (Saudi Arabia). Tower has a hight of 601m. It has world's biggest clock on its top (crossing the Big Ban London). Tower is a master piece of consturction. May ALLAH bless Saudi Arabia. Thanks to team Geo.