Look at the Christ Pantocrator icon carved into the salt rock. Church in Underground Salt Mine in Romania. Several hundred meters below ground, it was built for the workers of the salt mine and has been seen by very few people in the world.
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.
The Prague Astronomical Clock or Prague Orloj. The Orloj is mounted on the southern wall of Old Town City Hall in the Old Town Square and is a popular tourist attraction. 22 Reasons why Czech Republic must be in the Top of your Bucket Li