I want to know the answer to the following question:
What does Teheran, Isfahan, Mashhad, and Shiraz have in common?
All the background I'm provided with is that "The majority of the 300,000 tourist visas granted in 2003 were obtained by Asian Muslims, who presumably intended to visit important pilgrimage sites in Mashhad and Qom.". Is that enough to answer the question?
Answer: no