Ten persons were killed and seven others injured after a grotto collapsed in the Brazilian town of Santa Maria do Tocantins, officials said.The traditional Mass for All Saints Day was celebrated in the open air, outside the grotto known as the Stone House, which collapsed on Tuesday on a group of women who entered the structure at the conclusion of the service to pray, officials in Santa Maria told Efe news.The worshippers with the most serious injuries were admitted to the hospital.Police, firefighters and paramedics went to the site of collapse to provide assistance.