<P> The Ihram (white robes of pilgrimage) is meant to show equality of all Muslim pilgrims in the eyes of God, that there is no difference between a prince and a pauper . Ihram is also symbolic for holy virtue and pardon from all past sins . </P> <Ul> <Li> Al - Arba'een (Arabic: الأربعين ‎, "The Forty"), Chehelom (Persian: چهلم ‎, Urdu: چہلم ‎, "the fortieth (day)") or Qirkhi, Imamin Qirkhi (Azerbaijani: İmamın qırxı, امامین قیرخی, "the fortieth of Imam") is a Shia Muslim religious observance that occurs forty days after the Day of Ashura . It commemorates the martyrdom of Husayn ibn Ali, the grandson of Muhammad, which falls on the 20th or 21st day of the month of Safar . Imam Husayn ibn Ali and 72 companions were killed by Yazid I's army in the Battle of Karbala in 61 AH (680 CE). Arba'een or forty days is also the usual length of mourning after the death of a family member or loved one in many Muslim traditions . Arba'een is one of the largest pilgrimage gatherings on Earth, in which up to 31 million people go to the city of Karbala in Iraq . </Li> <Li> The second largest holy city in the world, Mashhad attracts more than 20 million tourists and pilgrims every year, many of whom come to pay homage to Imam Reza (the eighth Shi'ite Imam). It has been a magnet for travelers since medieval times . </Li> </Ul> <Li> Al - Arba'een (Arabic: الأربعين ‎, "The Forty"), Chehelom (Persian: چهلم ‎, Urdu: چہلم ‎, "the fortieth (day)") or Qirkhi, Imamin Qirkhi (Azerbaijani: İmamın qırxı, امامین قیرخی, "the fortieth of Imam") is a Shia Muslim religious observance that occurs forty days after the Day of Ashura . It commemorates the martyrdom of Husayn ibn Ali, the grandson of Muhammad, which falls on the 20th or 21st day of the month of Safar . Imam Husayn ibn Ali and 72 companions were killed by Yazid I's army in the Battle of Karbala in 61 AH (680 CE). Arba'een or forty days is also the usual length of mourning after the death of a family member or loved one in many Muslim traditions . Arba'een is one of the largest pilgrimage gatherings on Earth, in which up to 31 million people go to the city of Karbala in Iraq . </Li> <Li> The second largest holy city in the world, Mashhad attracts more than 20 million tourists and pilgrims every year, many of whom come to pay homage to Imam Reza (the eighth Shi'ite Imam). It has been a magnet for travelers since medieval times . </Li>

Who describe dams as pilgrim centres of development