Shetland: the Broch of Mousa

The Broch of Mousa is situated on an uninhabited island a short passenger ferry crossing from Mainland Shetland. This Iron Age tower is the best-preserved example of its kind, surviving to a height of over thirteen metres. I’ve visited numerous brochs across Scotland, and have read about their locations being strategic, but I was unprepared for the visual impact of this massive construction upon the landscape.

Above: A view to the island of Mousa from the Mainland of Shetland (Photo: Aaron Watson, 2019)

Above: The towering walls of the broch are clearly visible from the Mainland (Photo: Aaron Watson, 2019)

Above: Approaching Mousa on the ferry (Photo: Aaron Watson, 2019)

Once ashore, the broch is an easy walk along the coastline. There were stunning views across Mousa Sound in the sharp sunlight of the late afternoon.

Above: The Broch of Mousa is located on the more sheltered coastline of the island, and commands views across Mousa Sound towards the Mainland (Photo: Aaron Watson, 2019)

Above: The symposium field trip enjoying the light winds and sunshine at the Broch of Mousa (Photo: Aaron Watson, 2019)

Above: The broch is a commanding structure, and it is an unusual experience to be in the presence of a prehistoric building of this scale (Photo: Aaron Watson, 2019)

Above: The internal structure of the broch is remarkable. The architectural details within appear seem elegant for such a massive construction (Photo: Aaron Watson, 2019)

Above: Within the dry-stone walls of the broch are galleries and a winding staircase which leads to the top (Photo: Aaron Watson, 2019)

Above: The highest surviving level of the broch, which may originally have risen a further few metres (Photo: Aaron Watson, 2019)

Above: A shadow of the Iron Age - the evening sun illuminates the landscape around the Broch of Mousa (Photo: Aaron Watson, 2019)

Above: Looking down towards the west-facing entrance at ground level, with intricate apertures dividing the stone walling above (Photo: Aaron Watson, 2019)

Above: Looking vertically upwards from ground level in the Broch of Mousa. Brochs may have originally been roofed, but how this was achieved remains unknown (Photo: Aaron Watson, 2019)

The circular interior of the Broch of Mousa had unusual acoustics, since the walls reflected sounds around the cylindrical space. To my knowledge, the archaeoacoustic properties of brochs have not been explored in detail, although rather little is known about how their interiors may have been organised. For example, it is possible that the interior height may have been divided into floors.

Fortuitously, low sunlight reflecting upon the calm sea created an unexpected optical effect as it passed through the doorway of the broch. This aperture was sufficiently narrow for a diffuse optical projection of the scene outside to appear upon the opposing wall. I was able to characterise this as a camera obscura projection because the sparkling sunlight on the sea was inverted, appearing only at the top of the image.

Above: A short video showing a projected image of the sea inside the Broch of Mousa (Video: Aaron Watson)

Above: The single entrance from the outside. The walls may originally have been straight in profile, but have slumped slightly with age (Photo: Aaron Watson, 2019)

Above: Looking back to the Broch of Mousa in evening light, with Sumburgh Head on the horizon (Photo: Aaron Watson, 2019)

Above: A short video of the ferry crossing from Mousa to the Mainland (Video: Aaron Watson, 2019)