Bulgaria’s biggest carst spring pumps out 1200 liters of cold mineral water each second. Its name is Kleptouza and the spring is situated in the town of Velingrad.

Much of the spring’s water is used as tap water in Velingrad. The rest enters two lakes that empty into Maritsa and Chepinksa rivers.

The first lake was constructed in 1933 using municipal funding. Pine forests in the surrounding region have become a favorite walk and leisure time place. A restaurant was set up, as well.

Since April 2008, the park and the lakes became state property and have ever since been placed under the management of Velingrad municipality.

Verila is one of the smallest mountains in Bulgaria. It is located between the much bigger Rila and Vitosha.

The mountain lacks water. Very few rivers flow down its slopes. This characteristic gives its name. Verila comes from ancient Thracian as the opposite of Rila, which on its turn means water mountain.

Golyam Debelets is Verila’s highest point, 1415 m. The mountain is part of the climate division between the colder continental climate of the north and the much milder weather of the south.

Verila lacks major landmarks. It is suitable for one-day trips and picnics. Staying overnight there is not preferable since the region lacks hotels and cabins. The lack of water is another obstacle.

Sredna Gora (Средна гора) is a mountain range in central Bulgaria, situated south of and parallel to Balkan mountain range (Stara Planina) and extending from the river Iskar to the west and the elbow of Tundzha north of Yambol to the east. Sredna Gora is 285 km long, reaching 50 km at its greatest width. Its highest peak is Golyam Bogdan at 1,604 m (5,262 ft).

The mountain is divided into three parts by the rivers Topolnitsa and Stryama — a western (Zapadna or Ihtimanska Sredna Gora), a central (Sashtinska Sredna Gora) and an eastern part (Sarnena Gora).

The fauna of Sredna Gora is relatively poor compared to other regions of Bulgaria, with typical Central European species being present.

The Upper Thracian Plain (Bulgarian: Горнотракийска низина, Gornotrakiyska nizina) constitutes the northern part of the historical region of Thrace. It is located in southern Bulgaria, between the Sredna Gora mountains to the north and west; the Rhodopes, Sakar and Strandzha to the south; and the Black Sea to the east. A fertile agricultural region, the Upper Thracian Plain proper has an area of 6,032 km? and an average elevation of 168 m.

The plain is part of North Thrace or Northern Thrace (Северна Тракия, Severna Trakiya) (as opposed to Western Thrace and Eastern Thrace to the south), which refers to the whole of southern (sub-Balkan) Bulgaria east of the Mesta River and Sredna Gora (thus also including hilly or mountainous terrain).

The climate is transitional continental. The highest temperature recorded in Bulgaria occurred here: it was 45.2 °C at Sadovo in 1916. The precipitation is 550 mm a year. Important rivers are the Maritsa and its tributaries, the Tundzha, the Stryama, the Topolnitsa, and the Vacha.

Important cities include Plovdiv, Burgas, Stara Zagora, Pazardzhik, Asenovgrad, Haskovo, Yambol and Sliven.