The Cleaven Dyke in Perthshire, Scotland, is a linear earthwork (or cursus) comprised of two widely-spaced parallel ditches running either side of a central earth bank. It is around 2km in length and is dated to 3300BC.

The cursus first began as an oval burial mound. Later, a long tail was added making it a similar structure to the normal ‘long barrow’ formations of that period. Over a long period of time this ‘tail’ was extended further and further, eventually reaching a total length of 2km.

The Cleaven Dyke cursus is made up of 34 ‘tail’ segments which may possibly reflect the number of years it took to build.