Located in the northeastern part of the country in Khorasan province, Mashhad is distinguished mostly because of housing the shrine of Imam Reza, the eighth Shia Imam. During the Afsharid era, it was the capital of Iran and today, it is considered to be the second megacity of the country. It is probably the holiest city of Iran, as each year around 20 millions of local and foreigner pilgrims travel to Mashhad in order to visit the tomb of Imam Reza and the city as well.