The outer covering of heavenly Kaaba is known as Ghilaf-e-Kaaba or Kiswa. Nowadays the colour of Kiswa is black, but you may be amazed to know that it had been through many colours since its inception. Because the kiswa/Ghilaf-e-Kaaba is changed every year on the 9th of Zill-Hajj. The architectures use 120kg of gold and 25Kg of silver strings to script the verses of the Holy Quran on Kiswa.