WThe Arda is a 290-kilometre-long (180 mi) river in Bulgaria and Greece. It is a tributary of the Maritsa. Its source lies in the Bulgarian Rhodope Mountains near the village Arda, part of the municipality of Smolyan. It flows eastward past Rudozem, Kardzhali and Ivaylovgrad and enters Greece in the northern part of the Evros regional unit. It flows into the Maritsa on the border of Greece and Turkey, between the Greek village Kastanies and the Turkish city Edirne. In the Bulgarian section there are three hydroelectric and irrigation dams, Kardzhali Dam, Studen Kladenets and Ivaylovgrad Dam. The Bulgarian section is 229 kilometres (142 mi) long, making the Arda the longest river in the Rhodopes. The medieval Dyavolski most arch bridge crosses the river 10 kilometres (6 mi) from Ardino.
WByala reka is a river in the Rhodope Mountains in Southern Bulgaria, the longest tributary of Luda reka.
WThe Kardzhali Reservoir is a reservoir formed by the Kardzhali Dam, situated less than 1 km to the west of the town of Kardzhali in Kardzhali Province, Bulgaria. It is the second largest reservoir by volume in the country.
WThe Krumovitsa is a river in the eastern Rhodope Mountains of Bulgaria. The river valley is formed by the Krumovitsa River and the Djushun River together with the surrounding low mountain slopes.
WThe Rhodopes are a mountain range in Southeastern Europe, with over 83% of its area in southern Bulgaria and the remainder in Greece. Golyam Perelik is its highest peak at 2,191 meters (7,188 ft). The mountain range gives its name to the terrestrial ecoregion Rodope montane mixed forests that belongs in the temperate broadleaf and mixed forests biome and the Palearctic realm. The region is particularly notable for its karst areas with their deep river gorges, large caves and specific sculptured forms, such as the Trigrad Gorge.
WThe Stone Mushrooms is a rock phenomenon near Beli plast village in Bulgaria, on the road between Haskovo and Kardzhali. They are about 2.5 metres tall. The 3 hectares area was declared to be a natural resource on May 13, 1974, according to №РД-552 bill of the Ministry of Environment and Water. Interesting kinds of birds can be observed in the area: short-toed eagle, Egyptian vulture, red-rumped swallow, black-eared wheatear etc.
WThe Studen Kladenets Reservoir is the third largest reservoir by volume in Bulgaria after Iskar Dam and Kardzhali Dam. It is situated on the river Arda, and is created behind the Studen Kladenets dam, 30 km south-east of the town of Kardzhali. There are another two dams of the Arda - Kardzhali Dam to the west (upstream) and Ivaylovgrad Dam to the east (downstream).