to 13th century CE. Serer people The prehistoric and ancient history of the Serer people of modern-day Senegambia has been extensively studied and documented over the years. Much of the present knowledge of it comes from archaeological discoveries and Serer traditions rooted in the Serer religion. Material relics have been found in different Serer countries, most of which refer to the past origins of Serer families, villages, and Serer kingdoms. Some of these Serer relics included gold, silver, and metals. The objects found in Serer countries are divided into two types, the remnants of earlier populations and the laterite megaliths carved in circular structures with stones directed towards the East. The latter are found only in small parts of the ancient Serer kingdom of Saloum. They are described below. Senegambian stone circles The Senegambian stone circles are megaliths found in Gambia north of Janjanbureh and in central Senegal. The megaliths found in Senegal and Gambia are sometimes divided into four large sites: Sine Ngayene and Wanar in Senegal, and Wassu and Kerbatch in the Central River Region in Gambia. Researchers are not certain when these monuments were built, but the generally accepted range is between the third century BCE and the sixteenth century CE. Archaeologists have also found pottery sherds, human burials, and some grave goods and metals. The monuments consist of what were originally upright blocks or pillars (some have collapsed), made of mostly laterite with smooth surfaces. The construction of the stone monuments shows evidence of a prosperous and organised society based on the amount of labour required to build such structures. The builders of these megaliths are unknown, but some believe that they were Serer people. This hypothesis comes from the fact that the Serer still use funerary houses like those found at Wanar. Bura culture The Bura culture was located in the Middle Niger River valley of Niger and Burkina Faso. More specifically, the Iron Age civilization exemplified by the Bura culture was centered in the southwestern region of modern Niger and in the southeast region of modern Burkina Faso (previously known as Upper Volta). Based on radio carbon dating, the Sahelian Bura-Asinda culture may have begun in the 3rd century CE and lasted until the 13th century CE. Named for the Bura archaeological site located near Bura in southwestern Niger, the Bura culture produced a variety of distinctive artefacts made of clay, iron, and stone.