Age the Cetina culture, a geographically pervasive group with contacts throughout the Adriatic basin, became dominant. Extensive mound fields are recorded on the lower valley slopes at several locations around Cetina, Vrlika and Bajagić. As in other parts of Europe, the river appears to have been the focus of the intentional deposition of artifacts throughout prehistory. This is particularly true at the confluence of the Cetina and Ruda rivers at Trilj. The area is intimately associated with the heartland of the Delmatae and the area's strategic importance is emphasised by the citing of the legionary fortress at Tilurium (Gardun), just above today's city of Trilj, which guards the entrance to the valley from the south and the approach to the provincial capital at Salona. During the early medieval period, toponymic evidence suggests that the Cetina Valley and perhaps the river itself became a frontier between Slavic and Late Roman power. The area around Sinj eventually emerged as a centre of Slavic power and ultimately established itself as a heartland of the Early Croatian State, especially in the areas of its upper flow. During later periods the area was highly contested and passed between a number of regional and local powers before conquest by the Ottoman Empire during the early 16th century. After this it retained a frontier role between Ottoman Empire and Republic of Venice until the reconquest of the area 150 years later. Today canyon of the river Cetina is very popular among tourists looking for adventure activities like rafting, canyoning, zip-line, rock climbing, kayaking and other outdoor activities. References Rivers of Croatia Archaeological sites in Croatia Omiš Landforms of Split-Dalmatia County