Unsolved mysteries are creepy because they reveal the dark underbelly of society that remains unaccounted for. Hearing gristly tales of innocent peoples' deaths other unexplained incidences takes on an even more intriguing tone when you might never be sure what led to the events. Here are ten unsolved mysteries in the state of Pennsylvania.

1. Pennsylvania Bank Robber

A mysterious man robbed seven Pennsylvania banks between the years of 1977 and 1993. Each time, he entered the bank without a disguise under the guise of a customer who wanted to open a business card, then proceeded to shoot out the security cameras, hold the occupants of the bank hostage, and demand the tellers to give him all the money in the vault. It seems that at this point, he may never be identified.

2. Don Decker

Don Decker was a teenager in 1983 who was serving a prison sentence for receiving stolen property. He was allowed to leave for a week to attend his grandfather's funeral when oddly enough, rain began to fall sporadically from the ceilings above Don. The phenomena occurred consistently for a few weeks, causing a priest to be called in for an exorcism once he returned to jail, but Don never could explain the mysterious rainfall as anything but his grandfather's spirit. The rain stopped as suddenly as it began.

3. Cindy Song

Cindy was last seen in 2001, when she attended a Halloween party at Penn State University, where she was a senior. She disappeared after two friends dropped her off at her apartment late that night, bringing with her only her purse. A woman who matched her description was seen being forced into a car in Philadelphia a few days later-- investigations have focused on finding the man who authorities believe abducted her.

4. Dale Kerstetter

Dale Kerstetter was a security guard in Bradford when he disappeared one night in 1987. It appeared that he vanished without a trace. Security cameras revealed a masked intruder present shortly before his disappearance, leading authorities to believe he may have been abducted.

5. Route 22 Killer

David Hurley didn't expect a nighttime run to the store to buy donuts to be the last thing he ever did, but thanks to an unidentified man, it was. As he was leaving the store, a white car sideswiped his. When he exited his vehicle to exchange insurance information, the other driver shot him multiple times before driving away, leaving David severely injured. He managed to return home and died in the hospital hours later.

6. Kecksburg UFO Incident

Whether or not you believe in the existence of alien life in outer space, the Kecksburg incident is undeniably strange. On a quiet December night in 1965, millions of people in Canada and across six U.S. states witnessed what appeared to be a meteor blazing across the sky, dropping metallic debris, causing brush fires, and even resulting in sonic booms in the Pittsburgh area. Residents of Kecksburg reported finding an acorn-shaped object about the size of a small car in the woods, that was covered in what appeared to be hieroglyphics. The United States military roped off the area and took the object, though officially described the incident as a meteor landing.

7. Oliver the Chimpanzee

Oliver's trainers thought that he might be a chimpanzee-human hybrid or that he might be a missing link species because he had some bizarrely humanoid traits-- his face was flatter than those of his chimpanzee counterparts, he walked upright rather than on his knuckles, and he seemed to be more attracted to human women than to other chimpanzees. After his death, however genetic testing revealed that he was 100% chimpanzee, despite his odd behavioral traits.

8. Cherrie Mahan

Parents rarely expect their children to disappear in the 150 yard walk from the school bus to the driveway, but that's just what happened to Cherrie on February 22, 1985. Children on the school bus reported seeing a van with a ski mountain mural painted on the side that was following the bus. Authorities believe the driver of the van abducted Cherrie.

9. Hooded Grave Cemetery

In Catawissa, PA, about two dozen graves in a small cemetery have wrought iron cages covering the burial plot. Why did the people who buried these bodies feel the need to erect these structures? Possibly, they are a modern example of mortsafes, cages built over grave sites in the 18th and 19th centuries to prevent theft of the bodies. Or was the purpose something even more sinister... Local rumors speculate that the bodies were believed to be vampires that might rise out of the ground.

10. Sarah Rae Boehm

The mystery of who murdered fourteen year old Sarah Boehm remains unsolved more than twenty years after her disappearance in 1994. Authorities speculate that she may have been secretly involved with an older man who committed the crime. Her remains were identified in May 2003.

What other unsolved mysteries do you know of in our state?