The Toraja, or Toraya, are a group of peoples that inhabit the Cebeles islands, in Indonesia. Although they mostly profess the Christian faith, they still retain some of their ancient traditions, especially when it comes to honoring their dead.
The Toraja believe that death is not a sudden event, but that the soul of the deceased is separating from the body in a process that can take several months. For this reason, the dead are not buried immediately after death. Instead, they spend long periods living in the family home, where they receive food and are called "sick." This period can last for years if you are expecting a relative who lives in a distant region and who has to say goodbye to the deceased.
Even after the bodies have been buried, it is customary in the region to dig them up afterwards to bathe them, change their clothes, and invite them to family meals. In the past, leaves and herbs were used to preserve the bodies. Currently, the corpses are preserved with formaldehyde.
According to the Toraja, this tradition allows the deceased to gradually become accustomed to their new condition and to abandon, when they feel prepared for it, their physical body.
Source: BBC