Original sentence: It is New Zealand's oldest history museum.Its brief covers the territory of the old Otago Province, that is, New Zealand from the Waitaki River south, though its main focus is the city of Dunedin
Edited sentence: It is New Zealand's oldest and most extensive history museum.It is located in the heart of the city close to other prominent buildings such as the Dunedin Railway Station, some 500 metres from the city centre (The Octagon).Its brief covers the territory of the old Otago Province, that is, New Zealand from the Waitaki River south, though less emphasis is given to the area which later became the Southland Region