Skulls and bones in an ossuary with the remains of more than 50,000 people on October 19, 2012 under the Church of St. James in Brno, Czech Republic. Lost for some 200 years, the ossuary was discovered in 2001 during construction work under the Church of St James. #

Visitors enter the Sedlec Ossuary, a small Chapel beneath the Cemetery Church of All Saints in Sedlec, a suburb of Kutna Hora, Czech Republic, about 75 km east of Prague, on January 14, 2007. Although the ossuary dates back to the 14th century, its current decoration is made of some 40,000 human remains from the 18th century. #

Skulls are positioned at a village cemetery in Kuban near Trunyan, Bali, Indonesia, on March 21, 2007. Unlike the Balinese people, the people of Trunyan do not cremate or bury their dead but lay them out in bamboo cages to decompose. #

Skulls are positioned at a village cemetery in Kuban near Trunyan, Bali, Indonesia, on March 21, 2007. Trunyan ancient village is inhabited by people who call themselves "Bali Aga" or original Balinese who have maintained many of the old Balinese customs. #

Skulls and bones inside a shrine of the Santa Maria's church at the small village of Wamba, near Valladolid, Spain, on April 5, 2009. According to investigators, somewhere between the 15th and 17th centuries, the need for room in the surrounding cemetery prompted the opening of the oldest tombs and placing the bones in the ossuary. #

Skulls and bones, stacked in the Catacombs beneath Paris, France, on October 14, 2014. The Paris Catacombs recently opened to night-time tours, in addition to existing daytime trips. The subterranean tunnels, stretching 2 kilometers (1.2 miles), cradle the bones of some 6 million Parisians from centuries past and once gave refuge to smugglers. #

Human skulls preserved are exhibited at the Genocide memorial in Nyamata, inside Catholic church where thousands were slaughtered during the 1994 genocide in Rwanda. #

Victims' skulls are displayed on glass shelves inside one of the crypts at the Nyamata Catholic Church genocide memorial ahead of the 20th anniversary of the country's genocide April 4, 2014 in Nyamata, Rwanda. The memorial crypt contains the remains of over 45,000 genocide victims, the majority of them Tutsi, including those who were massacred inside the church itself. #

Mike Nkuzumuwami stands by the rows of human skulls and bones that form a memorial to those who died in the redbrick church that was the scene of a massacre during the 1994 genocide, in the village of Nyarubuye, eastern Rwanda, on March 27, 2014. #

The skulls and bones of some of those who were killed as they sought refuge inside the church, are laid out on shelves in an underground vault as a memorial inside the Catholic in Nyamata, Rwanda, photographed on April 4, 2014. #

A Romanian Orthodox priest holds religious services for the dead as nuns hold candles inside to the ossuary of Pasarea monastery during Easter celebration in Pasarea village, Bucharest, on May 4, 2013. #

Interior of St. Bartholomew's Church, or the Skull Chapel, in Czermna, Poland. Skulls and bones of several thousand people who were interred at the church were arranged in this manner over an 18 year period by local priest Waclaw Tomaszek, completed in 1794. #

Interior of St. Bartholomew's Church, or the Skull Chapel, in Czermna, Poland. The bones came largely from thousands who died from wars and epidemics in the 17th and 18th centuries. #