The present castle was built around 1819-1835 by Thomas Hooper for George Hawkins Pennant.
The large mansion house has a 115ft high keep where the family apartments were. A spiral staircase from a previous building can still be seen inside.
Although it is difficult to work out the cost of construction, it’s thought it would have been the equivalent to almost £50million today.
Inside, there is a bed that weighs 1 ton that was made for Queen Victoria for her visit in 1859.
It has one of the finest art collections in Wales, including a Rembrandt valued at £40million.
The castle overlooks the Snowdonia Mountains.
Lady Alice Pennant is said to have been standing at the top of the grand staircase wearing a corset dress.
The most common ghost seen at the castle is that of Lord Penrhyn, who died at age 70 in 1907. He is described as being tall, slim, a beard, wearing a long jacket with striped trousers and a high collared shirt. He is seen holding a book or papers, in the sitting room and the keep bedrooms.
Two ghosts have been spotted in and around the Dinorwic carriage exhibit at Penrhyn Castle.
This was a part of a train whose purpose was to carry slate the seven miles from Dinorwic Quarry to y Felinheli, formerly known in English as Port Dinorwic. 
A psychic who visited the Castle said she could “see the man very clearly wearing a top hat and a jacket with shiny buttons on it … he looked very authoritarian and had a hard stare.”
A volunteer saw a man through the windows while locking up the part of the museum with The Dinorwic Carraige in it. There have been multiple sightings of this man although it is unclear who he may be.
An engineer in the Railway Museum also claims to have seen a small boy with dark hair running near the Charles Engine. There have been multiple sightings of this man although it is unclear who he may be.
There has also been poltergeist activity in the shop, and strange heat changes in the corridors. A spirit has also been spotted in the nursery.
I visited this castle back in 2015, and it is an amazing place -Kaz
Project Paranormal 