After his death , his successor Muhammad bin Tughlaq , moved back to Delhi and left Tughluqabad to gradually crumble and decay .
The tomb of Ghiyas remains there in a very well preserved condition .
After his death , his successor Muhammad bin Tughlaq , moved back to Delhi and left Tughluqabad to gradually crumble and decay , although the tomb of Ghiyas remains there in a very well preserved condition .