Church of Our Saviour on the Spilled Blood, St Petersburg, Russia. As a ghost, I am looking for a castle to haunt. What about this one? I know it isn't technically a 'castle' but look at its magnificent size! I think it would still be splendid to haunt.
Humayun's tomb or Maqbara-e-Humayun is the tomb of the Mughal Emperor Humayun in Delhi, India. The tomb was commissioned by Humayun's first wife Bega Begum (Haji Begum). The tomb is one of UNESCO World Heritage Site.