What are the two other holiest cities in Islam other than the city that  is known for the Hajj?
Hajj The Hajj ( ; Arabic: ‎ ‎ "Ḥaǧǧ " "pilgrimage") is an annual Islamic pilgrimage to Mecca, the most holy city for Muslims, and a mandatory religious duty for Muslims that must be carried out at least once in their lifetime by all adult Muslims who are physically and financially capable of undertaking the journey, and can support their family during their absence. It is one of the five pillars of Islam, alongside Shahadah, Salat, Zakat, and Sawm. The Hajj is the largest annual gathering of people in the world. The state of being physically and financially capable of performing the Hajj is called "istita'ah", and a Muslim who fulfills this condition is called a "mustati". The Hajj is a demonstration of the solidarity of the Muslim people, and their submission to God (Allah). The word Hajj means "to intend a journey", which connotes both the outward act of a journey and the inward act of intentions.
Shia Muslims in the Arab world Islam is historically divided into two major sects, Sunni and Shia Islam, each with its own sub-sects. Large numbers of Shia Arab Muslims live in some Arab countries including Lebanon, Yemen, Iraq, Saudi Arabia, Kuwait, Oman, the UAE, and Qatar. Shia Muslims are a numerical majority in Iraq and Bahrain. Approximately half of the population in Yemen are Shia Muslims. Exactly half of Muslims in Lebanon are Shia Muslims. There is also a very large population of Shia Muslims living in the Arab Persian Gulf countries especially in Saudi Arabia. Approximately the whole population of East Saudi Arabia, the Eastern Province are Shia Muslims. Although government statistics claim that roughly only 20-40% of the Muslim population are Shia Muslims, there has been dispute to the authenticity of this figure and recent reports and investigations indicate that there is in fact a much larger population of Shia Muslims present, with estimate figures over 45% or even making the majority of Muslim population. Saudi Arabia follows a strict recently established sect of Islam, Wahhabism, there is little freedom of religion between the different sects even whilst all of the population are Muslims. Smaller Shia groups are present in Egypt and Jordan. Despite the heavy presence of Shia Muslims in some Arab countries, particularly among the population of the Persian Gulf Arab countries, they have been treated poorly throughout history. Additionally, in recent times, Shia Muslims along with Kurds have faced genocide by the pan-Arabist regime of Saddam Hussein. For both historical and political reasons, the Shia have fared rather poorly in much of the Arab world, and the topic of Shi‘ism and Shia groups is one of the most sensitive issues for the Sunni elite. This article discusses both the history of Shī‘a Islam in the Arab world from the dawn of Islam and their current situation in the Arabic-speaking world.