The infamous Hellfire Club building was built in 1725 by William Connolly, speaker of the Irish parliament in Dublin, Ireland. He chose a site on Montpelier Hill in the Dublin Mountains, with a spectacular view over the city, which is still enjoyed by hill-walkers and hikers today. The building was supposed to be a hunting lodge, but it soon took on a more sinister role as a base for the Dublin branch of The Hellfire Club an association of young aristocrats dedicated to a life of debauchery.

The building was cursed from the start, having been built on the site of an ancient Stone Age burial cairn rocks from the cairn were allegedly used in the construction of The Hellfire Club building. It seems that this desecration has truly damned the place; even people living in modern housing estates at the foot of the mountains report an unusually high level of paranormal activity in their houses.

The members of The Hellfire Club used the lodge for holding black masses, and it is believed that both animal and human sacrifices took place there. In particular, they were known to sacrifice cats. Legend has it that the Devil himself visited his loyal followers in this building, and even today many visitors are troubled by an odd smell of brimstone.