A Muslim must perform Hajj once in a life time provided expenses can be met without borrowing or owing any money to anyone, health is good and there is safety of the way. Hajj is the recreation of some of the trials and tribulations of Prophets Abraham and Ishmael and Hagar, the wife of Abraham, with a few additional rituals. The Hajj lasts for five days from the 8th to 12th of Dhu al-Hijjah. Approximately two million people perform Hajj every year. The above mentioned five rites of worship are also called the five pillars of Islam.
Pillars are supporters of roofs and walls.
If the pillars fall down there is no building left. Similarly, if a Muslim is not doing his five times daily salah, this pillar is absent from his building of Islam and part of the building is destroyed. He may claim to be a Muslim but in practice he is a hypocrite. The same analogy is applied to other pillars. A Muslim scientist must be the best among his peers, a doctor must be the best, a car mechanic must be the best and so on.