Geograph - photograph every grid square

The Devil's Dyke is one of the best preserved Anglo-Saxon earthworks of its kind in the country dating from the 5th or 6th century AD. It consists of a 7.5 miles (12.1 km) long bank and ditch running in a south-east direction from the village of Reach to Woodditton. When it was created, it sealed a narrow land corridor between the southern edge the then undrained and water-logged fenland in the north-west, and dense woodlands in the south, so making circumvention difficult and forming an effective barrier. The dyke crossed three important Roman roads, including the ancient Icknield Way, and may thus have served as a way of controlling trade and movement in and out of the area.

It was probably built by the East Anglians against their Mercian neighbours. The Anglo-Saxon Chronicle and other sources record the frequently tense relations between the two kingdoms, and it is likely that this provoked the need to strengthen the border and control access.

It is a Scheduled Ancient Monument (SAM). It also contains chalk grassland of international importance and has been designated as a Site of Special Scientific Interest (SSSI) and part is a Special Area of Conservation (SAC).

Try Archive Link for more information.

In the United Kingdom, a scheduled monument is a 'nationally important' archaeological site or historic building, given protection against unauthorised change.
There are about 20,000 scheduled monuments in England representing about 37,000 heritage assets. Of the tens of thousands of scheduled monuments in the UK, most are inconspicuous archaeological sites, but some are large ruins.
Wikipedia: Link

Newmarket Racecourse, is a horse racing venue in the town of Newmarket, Suffolk, comprising two individual racecourses, the Rowley Mile and the July Course. Newmarket is often referred to as the headquarters of British horseracing and is home to the largest cluster of training yards in the country and many key horse racing organisations, including Tattersalls, the National Horseracing Museum and the National Stud. Newmarket hosts two of the country's five Classic Races - the 1,000 Guineas and 2,000 Guineas, and numerous other Group races. In total, it hosts 9 of British racing's 36 annual Group 1 races.