I don't know if mine was the most unusual but it was such a Blessing to find! It was of my Grandfather's Grandma, who was also his Aunt. Martha E. Farmer married Grandpa's Uncle Jack after her husband passed away. Grandpa's Mom was eight years old at the time.
Martha's tombstone was a tall cylindrical one. We found it in Mount Comfort Cemetery north of Springfield, MO. It stood near my Great Great Grandfather Wiley Farmer's stone, but turned away from it an on an angle. I would have expected it to have been in line with it. When Grandpa took us there years ago to see his family stones, he did not show us Martha's. I do not know if he wasn't aware of it there or forgot, but we found it. The wording was so faded I was afraid we wouldn't be able to read it. I put dirt over the inscriptions and there they were. Martha E. Farmer, her dates and the scripture, "In my house are many mansions!" What a Blessing to me to find Martha and also find out she was a Christian.
Very unusual. However, I visited the Elmwood Cemetery in KC this weekend. They have "crypts" back in the hills with gates. Not seen that here in Missouri before. Beautiful monuments. It is an Historical site now but run by volunteers. If you like cemeteries, you should visit it just to see the beautiful elms (most are gone around Missouri) and the attractive burial places.