Trebišnjica River

The Trebišnjica is a Herzegovinian sinking river 96.5 kilometers long, and with its underground courses it totals 187 kilometers. It rises near Bileća, at an altitude of 398 meters, and its final destination is the Adriatic Sea — through underground channels it reaches the Ombla River, which flows into the sea near Dubrovnik. The name comes from the Proto-Slavic word trjeba, meaning sacrifice or altar, reflecting its ancient cultural role.

Traces of human presence more than 40,000 years old have been found along its banks. Before the construction of hydroelectric plants, it was considered the longest natural sinking river in Europe. It flows through Trebinje in a calm, clear stream, attracting anglers, divers, and day-trippers. It is home to the endemic gaovica and the human fish that inhabits its underground channels. The well-known excursion areas Studenac and Lastva are located along its banks, and the city is connected by Arslanagića Bridge, Ivo Andrić Bridge, and Kameni most.