The site was farther from the sea than it is today, and it is possible that Skara Brae was built adjacent to a fresh water lagoon protected by dunes. Although the visible buildings give an impression of an organic whole, it is certain that an unknown quantity of additional structures had already been lost to sea erosion before the site's rediscovery and subsequent protection by a seawall. Uncovered remains are known to exist immediately adjacent to the ancient monument in areas presently covered by fields, and others, of uncertain date, can be seen eroding out of the cliff edge a little to the south of the enclosed area.