International Museum of Spiritual Investigations.

Located at 231 Baltimore St. in a 185-year-old house that survived the three-day Civil War battle, the museum opened in early March.

"About 10 years ago, Chris and I started coming here annually to research paranormal activity," said Williams, who moved to Gettysburg from New Jersey five years ago. "About a year ago, we decided to create a place to gather in all this evidence, so we decided to start a museum."

Small but growing, the museum features three rooms displaying photos, videos and even ghostly voices.

The United States Room focuses on sightings and people who have played a prominent role in spiritualism in America. Included is the story of the spiritualist community of Lily Dale, N.Y., which formed in the mid-19th century. It also features the story of William Mumler, whose camera work, Williams said, was "pretty much the birth of spiritual photography."

Accused of being a fraud by no one less than showman P.T. Barnum (Mumler was tried and acquitted), his work became world-famous. Of special note was his portrait of Mary Todd Lincoln, seated, with the ghostly figure of her slain husband touching her shoulder.

Among other works in this room is a recent photo by a Civil War re-enactor taken without flash on Seminary Ridge. The picture shows apparitions, one appearing to wear a Civil War hat, or kepi, walking through the darkness.

"They counted 14 soldiers crossing the field on Seminary Ridge," Williams said. "It's just one of many unexplained photos."

The International Room showcases mysterious incidents from around the world, including what might be the most well-regarded ghost photo ever taken, that of the "Brown Lady" descending a staircase at Raynham Hall in England in September 1936.

There also is a photo of the Ghost Club, founded in London in 1862, which included such notable members as Charles Dickens, Sir Arthur Conan Doyle and Harry Houdini.

Williams said he is always looking for more paranormal information, whether it's in the form of video, audio or photo, or of weather-related or electromagnetic phenomena.

"Any investigator or any ghost enthusiasts who have collected evidence can come in and donate whatever they can," Williams said.

In the short time the museum has been open, Williams said, he has received one or two pieces of evidence per day.

Williams has had many strange experiences during his 13 years of looking into ghostly doings, including several encounters in the museum itself. He and the others have caught fleeting glimpses of figures and heard voices and footsteps.

"We've had our share of sightings," he said. "Visuals, audio and our names called out, to being touched and tugged."