Mandatory Credit: Photo by APAImages/Shutterstock (12222660av) Palestinians pray on the first day of Muslim holiday of Eid al-Adha, in Khan Younis, in the southern Gaza Stripon July 20, 2021. Eid al-Adha, or Feast of Sacrifice, Islam's most important holiday marks the willingness of the Prophet Ibrahim to sacrifice his son, is to start on Tuesday with Muslims slaughtering animals and celebrating the end of their annual hajj pilgrimage to the holy city of Mecca in Saudi Arabia. Palestinians pray on the first day of Muslim holiday of Eid al-Adha, Khan Younis, Gaza Strip, Palestinian Territory - 19 Jul 2021