Achill Archaeological Field School is based at the Achill Archaeology Centre in Dooagh, which has served as a catalyst for a wide array of archaeological investigations on the island. It was founded in 1991 and is a training school for students of archaeology and anthropology. Since 1991, several thousand students from 21 countries have come to Achill to study and participate in ongoing excavations. The school is involved in a study of the prehistoric and historic landscape at Slievemore, incorporating a research excavation at a number of sites within the deserted village of Slievemore. Slievemore is rich in archaeological monuments that span a 5,000-year period from the Neolithic to the Post Medieval. Recent archaeological research suggests the village was occupied year-round at least as early as the 19th century, though it is known to have served as a seasonally occupied 'booley village' by the first half of the 20th century. A booley village (a number of which exist in a ruined state on the island) is a village occupied only during part of the year, such as a resort community, a lake community, or (as the case on Achill) a place to live while tending flocks or herds of ruminants during winter or summer pasturing. Specifically, some of the people of Dooagh and Pollagh would migrate in the summer to Slievemore and then go back to Dooagh in the autumn. The summer 2009 field school excavated Round House 2 on Slievemore Mountain under the direction of archaeologist Stuart Rathbone. Only the outside north wall, entrance way and inside of the Round House were completely excavated.