I thought I would share with you my very first encounter with a ghost or a ghost door, to be specific.
When I was a child, my family and I used to take this trip to a castle (Called Tidö Slott) about 2 times a year. It contained a toy-museum, with old toys from the royal family and such. Before it was a museum it was the home of the royal family, I believe in the 1600's.
I remember this one time, I think I was about 5-6 years old, when my dad and I stayed a bit longer in one room and the rest of the family went on without us. When my dad and I went out of the room, we looked down both ways in a big hallway. To our right, we saw the rest of the exhibition. To our left, we saw a big brown old-looking door with a black, round handle on it. The door was partly open, and you could see light coming out and a brick wall behind it. We decided to go to our right, and then explore the rest behind that door. About one half hours later, we took our family back to the hallway to show them the last part behind the door. But when we got there, the hallway ended with a white wall. We got startled, but thought that we simply where in the wrong spot. We looked through the whole exhibition, but we never found the wooden door again.
About 2 years later, we saw this paranormal TV-show on TV, and it was about the castle. They talked about how it was haunted and suddenly the showed a hallway that ended with a white wall, saying "This is where the cellar door used to be, but it was blocked up after the little prince went down here and was never found again." Both my dad and I said "That's the hallway where we saw the door!" And it was. It's strange that we actually saw the door, that hasn't been there for 400 years.
I've been to the castle after that experience, but I never saw the door again.