It consists of medieval, Viking, Pictish, and Iron Age remains and has been a settlement for thousands of years, each new generation adding buildings, and levelling off old ones.
An arc of the broch wall was exposed in one side of a green mound during the building of the perimeter road at the airport at Sumburgh Head.
[1] Since 1995, University of Bradford staff and students, professional archaeologists and local volunteers have been excavating the site and cataloging the finds.
In the summer, costumed guides provide tours of the site and the replica Iron Age and Pictish buildings.
[1] East of this building and closer to the broch, a circular inward-tilting arrangement of stones appeared to be the partially collapsed top of the roof of a corbelled cell.
[1] A slightly later roundhouse (Structure 21), east of the broch, had the greatest diameter of any of the buildings on site: approximately 12 metres internally.