Mashhad (Persian: مشهد, IPA) is the second most populous city in Iran and capital of Razavi Khorasan Province. It is located in the northeast of the country, close to the borders of Turkmenistan and Afghanistan. Its population was 2,749,374 at the 2011 census and its built-up (or metro) area was home to 2,782,976 inhabitants including Mashhad Taman and Torqabeh cities. It was a major oasis along the ancient Silk Road connecting with Merv in the East. The city is named after and revered for housing the tomb of Imam Reza, the eighth Shia Imam. Every year, millions of pilgrims visit the Imam Reza shrine and pay their tributes to Imam Reza. The Abbasid caliph Harun al-Rashid is also buried within the shrine. Mashhad has experienced the rise and fall of many governments over the course of history. Many Arab, Turkic, and especially Mongolian and Afghan tribes have brought great changes in the language, ethnicity and culture of the people each in their own time. Surprisingly, Mashhad enjoyed relative prosperity in its economy in the Mongol period. Mashhad is famously known as the city of Ferdowsi, the Iranian poet of Shahnameh, which is considered to be the national epic of Iran. The city is the hometown of some of the most significant Iranian literary figures and artists such as Mehdi Akhavan-Sales, the famous twentieth-century poet, and Mohammad-Reza Shajarian, the traditional Iranian singer and composer. Ferdowsi and Akhavan Sales are both buried in Tus, an ancient city that is considered to be the main origin of the current city of Mashhad. On 30 October 2009 (the anniversary of the death of Imam Reza), Iran's then-President Mahmoud Ahmadinejad declared Mashhad as "Iran's spiritual capital".