The vastest lowland in Bulgaria and on the Balkans, is the Upper Thrace. (Plovdiv is the metropolis of the region). It is about 180 km long and 50 km wide. Its overall area is 6032 square km.

The largest bay is the Bourgas Bay on the Black Sea coast. It goes 31 km into the land. At its widest, it measures 41 km, and its deepest point is 25 m.

The largest coastal lake is the Varna Lake that covers an area of 18 square km. It is also the deepest - 19 m.

The largest glacial lake is Smradlivoto in the Rila Mountain. It covers 21.2 hectares.

The highest mountain is Rila. Its highest peak Moussala rises to an altitude of 2925 m above the sea level. This is the highest point on the Balkans. The first written evidence of the peak being climbed refers to King Philip II, the father of Alexander the Great.

The highest glacial lake is Popovoto, in the Pirin Mountain, situated at 2715 m above the sea-level.

The highest waterfall is Raiskoto Praskalo /Paradise Sprayer/ - 124 m. It is not far away from the Botev peak in the Balkan Range. The total number of falls in Bulgaria is nearly 300, 70 of which are state-guarded.

The only Bulgarian extinct volcano is Kozhukh (281 m above sea level). It is not far from the southwestern town of Petrich.

The greatest number of mineral springs are to be found in the town of Velingrad - more than 70.

The longest cave is close to the village of Bosnek, in the Vitosha Mountain near Sofia - over 15 km. Six underground rivers have dug out the labyrinths of its galleries. As many as 4000 caves have been investigated and mapped in Bulgaria so far.

The lowest temperature, measured in an inhabited locality, was registered in the winter of 1947 in the town of Tran, west of Sofia - minus 38.3 degrees centigrade.

The highest temperature was measured in the summer of 1916 in Sadovo, near Plovdiv - 45.2 degrees centigrade.

The heaviest rain was recorded on 21 August 1951 in the neighborhood of the port of Varna, where within only 24 hours there were rainfalls of 342 mm. The average annual precipitation for the country is 650 mm.

The most prolonged fog occurred in December 1948 in Sofia - 29 days and nights. At that same time, the fogs in Plovdiv and Lom stayed for 28 days.

The hottest mineral spring is in Sapareva Banya near the town of Dupnitsa. Its temperature is 103, 8 degrees centigrade. According to some sources, this is the hottest spring in Europe.

The oldest tree is an oak growing in the village of Granit near Stara Zagora. Its age is estimated at about 1650 years. The crown of this oak-tree covers 1017 square m; the circumference of its trunk is 7, 45 m and its height - 23, 40 m.

The “Baikusheva Mura” /white fir/ in Pirin Mountain is as old as the Bulgarian state - 1300 years.

The largest bear in Europe by 1936 fell a victim to man in the neighborhood of Borovets, the famous ski resort in Rila Mountain. This “record” was recognized as a record at an international hunting exhibition in Berlin.

Bisons in the Bulgarian lands disappeared as early as the Middle Ages. In 1961 the reserve near the town of Razgrad acquired 2 couples of bisons and settled them in the Voden forest. Nowadays there are several dozens of bisons in different Bulgarian preserves.

The largest amphibian is a turtle, which was caught and then set free near the town of Krumovgrad in 1987. It weighed 5 kg, was 35 cm long, and of the same height, 29 cm wide and 100-120 years old - i.e. at the age limit of animals of the European fauna. Another turtle of similar dimensions was caught some 80 years ago in the neighborhood of Kotel, a town in Central Bulgaria.

The rarest animal species is the Black Sea seal of which only 5-6 are left now. They inhabit the caves along the shoreline around the Black Sea capes of Kaliakra and Masslen.

The farthest migration is that of the eels, which live in the Bulgarian rivers, but spawn as far away as the Sargasso Sea, east of Florida, U.S.A.

The longest river running only across Bulgarian territory is Iskar - 368 km.

The last lynx in Bulgaria was shot in 1941 in the Rila Mountain.

The last lion in the Bulgarian lands was killed during the campaign of the Persian king Xerxes (as evidenced by Xenophon).