The Casma–Sechin culture (alternatively Sechin Complex) (c. 3600 BCE – 200 BCE) of Peru refers to the large concentration of pre-historic ruins in the valleys of the Casma River and its tributary the Sechin River and along the nearby coast of the Pacific Ocean. The ruins include major archaeological sites such as Sechin Bajo, Sechin Alto, Cerro Sechin, Mojeque (Pampa de las Llamas-Moxeke), Chankillo, and Taukachi-Konkan, as well as other smaller sites. Most of these inland sites are found in the river valleys about 20 kilometres (12 mi) distant from the ocean. The seaside sites of Huaynuná and Las Haldas are found about 20 kilometres (12 mi) north and south of the mouth of the Casma River on the coast.