Reward for 2 accepted Haj for those who visit the grave of the Holy Prophet (Sallallahu alaihi wa sallam)
There is a Hadith:
Translation: Whoever performs Haj, then comes to my Masjid to visit me, for him (or her) the reward of 2 accepted Haj is written. (Sunan Dailami, Jame’ Ul Ahadith Wal Maraseel, Hadith No. 21996; Jame’ Ul Kabeer, Hadith No. 4727; Kanz Ul Ummal, 12370)