The Castle of The Two Sisters

The Castle of the Two Sisters, alternatively called the Castle of the Royal Pony Sisters, is the castle that Princess Celestia and Princess Luna used to live in a thousand years prior to the beginning of the series. It is located deep within the Everfree Forest and, according to the book The Journal of the Two Sisters, was built by the princesses, Melvin the manticore, and Star Swirl the Bearded. It now stands abandoned and dilapidated as much of it was destroyed during the battle between Celestia and Nightmare Moon.