Mausoleum of Bibi Maryam.
Qalhat is about 20km from Sur, follow the new coastal road from Muscat.
The mausoluem built by the wife of Baha al-Din, Maryam, is thus call the Bibi Maryam mausoleum. Located on the coast near the town of Qalhat, described by Marco Polo and visited by Ibn Battuta in the second quarter of the fourteenth century.
Philip Ward’s Travels in Oman about Qalhat:
At the end of the fourteenth century Qalhat was struck by a heavy earthquake that destroyed many of the city’s buildings and falaj systems. In 1507, the Portuguese arrived in Oman ransacking Quriyat and then in the following year they destroyed Qalhat, killing many of the local population.
“They did not stop to put fire to the building until it was completely burnt down….”
See entry World Heritage Centre from the link below.