The Tomb of Ferdowsi is located in Tus, near the city of Mashhad, in the Razavi Khorasan province of Iran. You can explore more about this magnificent historical site here.
The Mausoleum of Attar of Nishapur is situated in Nishapur, also in northeastern Iran. It is known for its unique octagonal structure and is situated near the Mausoleum of Omar Khayyám. More details can be found here.