Mound - Artificial heaped pile of earth, gravel, sand, rocks, or debris

"A mound is a heaped pile of earth, gravel, sand, rocks, or debris. Most commonly, mounds are earthen formations such as hills and mountains, particularly if they appear artificial. A mound may be any rounded area of topographically higher elevation on any surface. Artificial mounds have been created for a variety of reasons throughout history, including ceremonial, burial (tumulus), and commemorative purposes. - Wikipedia"