Silbury Hill is a prehistoric artificial chalk mound near Avebury in the English county of Wiltshire. It is part of the Stonehenge, Avebury and Associated Sites UNESCO World Heritage Site. At 39.3 metres (129 ft) high, the hill is the tallest prehistoric man-made mound in Europe and one of the largest in the world; it is similar in volume to contemporary Egyptian pyramids. The site is in the care of English Heritage.

Skipsea Castle was a Norman motte and bailey castle near the village of Skipsea, East Riding of Yorkshire, England. Built around 1086 by Drogo de la Beuvrière, apparently on the remains of an Iron Age mound, it was designed to secure the newly conquered region, defend against any potential Danish invasion and control the trade route across the region leading to the North Sea. The motte and the bailey were separated by Skipsea Mere, an artificial lake that was linked to the sea during the medieval period via a navigable channel. The village of Skipsea grew up beside the castle church, and the fortified town of Skipsea Brough was built alongside the castle around 1160 to capitalise on the potential trade.