The On-I-Set Wigwam in Onset is a building with no equal in the entire world. It is the oldest spiritualist summer camp in the country and still holds religious services to this day.

"We have an obligation to keep it going," said Gerry Pearle, speaking at the 120-year-old Wigwam at 9 Crescent Place on Sunday afternoon.

Pearle spoke about the history of Spiritualists, the Wigwam and the effort to preserve a unique part of Onset and American history.

Spiritualism is a religion that believes spirits of the dead have the ability to communicate with the living through mediums. The roots of Spiritualism started in Kentucky in the early 1800s with religious services called "camp meetings." These meetings would take place in the summer when it was too hot to meet in the community church.

The meetings were more informal than a church service and had a strong social component to them. These meetings quickly became popular across the country and by the 1870s there were campgrounds everywhere. Spiritualism emerged from Protestantism; at the time there were six Protestant campgrounds on Cape Cod.

In the late 1870s a group of Boston businessmen who were Spiritualists set out to find a plot of land to build the first spiritualist camp on the Cape. After being turned away from a plot of land in Buzzard's Bay, they fell in love with Onset.

"This was all wilderness," Pearle said. "When they saw the Bay they knew this would be the place."

The businessmen bought 150 acres of land from Benjamin Gibbs, an Onset entrepreneur, and formed the Onset Bay Grove Association. The campground was dedicated on June 14, 1877 with more than 1,000 people in attendance at the Band Shell in present day Onset Village.

Pearle said in the 20 years that followed Onset was bursting with life because of the Spiritualists' popularity. She said there were hotels, restaurants, two dance halls, and a bowling alley, just to name some of the amenities.

But in 1892 a book was released entitled, "The Vampires of Onset," which detailed some of the fraudulent practices going on around the country under the guise of Spiritualism. None of these deceitful practices however, happened in Onset, it was just the most well-known spot for Spiritualists and made for a sensational title. Nonetheless, the book (which was banned in Wareham until 1994) hurt the economy of the area and caused a schism in the Spiritualists who ran the campground.

Many decided to rebrand themselves, centering their readings and services around well-known celebrities of the time. But a small group of 20 Spiritualists stayed true to their roots of relying on communication with Native American spirits to provide their readings and services.

Pearle said this small group were told by the Native American spirits to erect a building on Waban Grove and to build something recognizable to the Native Americans. The spiritualists claim the Native Americans told them to paint the Wigwam red, the roof green and to build it 26 feet high so any spirit could find it.

The Wigwam was built in 1894 with significant financial backing from Mary Weston, who was the first president of the Wigwam Spiritualists. Her presidential chair is inside the Wigwam to this day.

The Wigwam was in disrepair for decades during the late 20th century, until Pearle and others raised the funds to renovate the building. On July 30, 1994, 100 years to the day the wigwam was built, the restoration process was completed.

Pearle said that the wigwam is one small step from being placed on the National Register of Historic Places.

"How sad it would be to have this building lost if people didn't know about it or care about it," she said.