I used to visit graveyards until one day about two years ago in France I took my then 12 year old son into an interesting one that had loads of ornate family crypts.
On entering the graveyard, I told him not to touch anything.
He put his hand on the front of a crypt that was about 3 feet of the ground and it opened! I nearly had heart failure and jumped to push the concrete door (about 3ft wide and 2ft high) back in place. When we tried to let go again, it fell forward and we had to continue to hold it.
We called the caretaker who screamed at us and no amount of apologising or explaining that he had literally just placed his hand on the front of the crypt would do.
As the door was going to fall to the ground if we let go, we agreed to place it on the ground so it wouldn't get broken. My biggest fear was of what we would see when we removed the door, which was sooo heavy we feared dropping it!
Fortunately, the crypt was cemented up behind the door so we didn't see a coffin or shrouded figure.
We left our name, address and telephone number with the caretaker and told her if the owner of the crypt wanted to contact us we would be happy to pay to have the door replaced and were extremely sorry.
I haven't been into a graveyard since.