According to popular legend, Shah Jahan decided to construct another Tajmahal in black marble on the other side of the river Yamuna and to connect the two by a bridge. This structure was intended to be his own tomb. It has been recorded almost contemporarily by a French merchant Tavernier : "Shah Jehan began to build his own tomb on the other side of the river but the war with his sons interrupted his plan and Aurangzeb who reigns at present is not disposed to complete it".


Later gazetteers and guide books mention this story almost invariably. The irregular position of the cenotaph of Shah Jahan as compared to that of Mumtaz Mahal which occupies the exact centre of the hall is said to be proof of this assumption. The Mehtab Burj and the wall adjoining it opposite the Tah Mahal are generally said to be the foundations and remains of the proposed plan.


Many scholars, however, believe that this idea belongs to fiction rather than history. The traces which are identified as the foundations of the second Tajmahal are actually the enclosing wall of a garden founded by Babar. The irregular position of Shah Jahan's cenotaph in comparison to Mumtaz Mahal's, is similar to that at the tomb of Itmad-ud-Daulah, and thus should not be of any striking significance. Besides, according to Islamic law, bodies are buried with their faces towards Mecca and legs towards the south, and the husband is placed on the right hand side of his wife. The interpretation that the cenotaph of Shah Jahan was not meant to be placed here appears to be superfluous.