The highway north from Nikšić meets the Piva River after passing through 40km of verdant farmland. It then tangos with the river until they both reach the border at Šćepan Polje. The river was blocked in 1975 by the building of the 220m-high hydroelectric Mratinje Dam (Brana Mratinje), flooding part of the Piva Canyon (Кањон Пива) to create the tremendously turquoise Lake Piva (Pivsko Jezero), which plummets to depths of more than 180m.
The road alongside the river is a feat of engineering in itself, clinging to the cliffs and passing through 56 small tunnels carved out of the stone. The narrow but equally spectacular route through the mountains from Žabljak joins this road near Plužine, the Piva region's unofficial capital. Heading north from here the route gets even more dramatic, with the steep walls of the canyon reflecting in the toothpaste-blue waters below.