So this happened in my home town in a house that was built in the 1850's that my parents bought and moved into. The basement was scary as it was just a cold damp room with just one lightbulb to light the whole thing. We used it for storage. One day my sister who was 10 at the time and me who was 8 at the time walked into my room and said "Hey "Fine_Cats_And_Cigars, lets go searching around in the basement, we might find something cool!". So we ran into the basement and spent the next hour looking around in all the storage in the basement. I discovered a catacomb that ran all under the house. When I found it she got extremely scared and said we should go upstairs. I go up first and when I am up I can still hear the sound of her running up the old wooden stairs, but I look to my right and see my sister sleeping on the couch in the living room. I looked behind me and no one was there. I ran to my sister and said what happened and she said she was asleep for the last 2 hours and I must have been dreaming.

To this day no one believed me, until about 10 years later. I was helping my father and I were renovating the basement into a living room for family activities. We were both downstairs laying hardwood over the concrete floor when I decide to go up to get us lunch. I run upstairs, make lunch, and call my dad upstairs. I immediately hear the loudest scream I have ever heard my dad do in his life and heard him rapidly running up the stairs. While panting he told me that I was in the catacombs cleaning it out, but he could still see me. He hears me upstairs call him and runs up. We go back down and the vacuum was in the storage upstairs and no one was in the catacomb. 

We have no idea what happened, but he still lives there and the basement has been renovated. It scares me to think about it.