Hundreds of thousands of mourners, clad in black, have congregated outside the Grand Mosalla in Tehran to pay their respects to Iran's late Supreme Leader, Ayatollah Ali Khamenei. His body is currently being displayed at the mosque and will remain there until Monday before embarking on a tour across Iran and Iraq. Authorities anticipate that approximately 15-20 million people will attend the funeral ceremonies over the coming days, marking more than four months since Khamenei's death in US and Israeli strikes. The gatherings have been characterized by chants against the United States and calls for retribution for the ayatollah's assassination. One mourner, a 37-year-old professor named Reza, stated, "We are here because we promised the supreme leader we would stand by him until the end." The funeral procession is expected to be the largest in terms of attendance as a proportion of the country's population and will culminate in Khamenei's burial at the Imam Reza Shrine, Iran's most significant pilgrimage site, next Thursday. In addition to the six-day procession, commemorative events will continue for 40 days beyond the first anniversary of his burial. Ayatollah Khamenei was succeeded by his son Mojtaba, who has not been seen in public since assuming the role, raising questions about his health and whether he will attend the funeral proceedings.