Editing Geography of Bulgaria (section)

=== Transitional region ===
[[File:Rose Valey Bulgaria 01.JPG|thumb|left|250px|alt=a valley with roses|The Rose Valley]]
The Transitional geomorphological region encompasses the territory between the Balkan Mountains and the Rilo-Rhodope Massif and has complex, mosaic relief composed mainly of medium-high and low mountains, valleys and plains. The altitude decreases from west to east.<ref name="donchev35">{{harvnb|Donchev|Karakashev|2004|p=35}}</ref> This region includes the [[Sub-Balkan Valley|Sub-Balkan valleys]]; the mountains and valleys of the Kraishte region, such as [[Ruy Mountain]], [[Miloslavska planina]] and [[Milevska Planina]]; the mountain ranges [[Lyulin Mountain|Lyulin]], [[Vitosha]], [[Sredna Gora]], [[Strandzha]] and [[Sakar (mountain)|Sakar]]; the [[Dervent Heights]]; as well as the fertile [[Upper Thracian Plain]].<ref name="donchev35"/> The highest point is [[Cherni Vrah]] in Vitosha at 2,290&nbsp;m.<ref name="donchev35"/>

The Sub-Balkan valleys include eleven valleys, situated between the Balkan Mountains in the north and Vitosha and Sredna Gora in the south. With an area of 1,186&nbsp;km<sup>2</sup> and an average altitude of 550&nbsp;m, [[Sofia Valley]] is the largest and contains the nation's capital, [[Sofia]]. The [[Rose Valley, Bulgaria|Rose Valley]] encompasses the valleys of [[Karlovo Valley|Karlovo]] and [[Kazanlak Valley|Kazanlak]] and is renowned for its [[Rosa × damascena|rose-growing industry]], which has been thriving there for centuries, producing 85% of the world's [[rose oil]].<ref name="Donchev 2004 107">{{harvnb|Donchev|Karakashev|2004|p=107}}</ref> The Kazanlak Valley is also known as the [[Valley of the Thracian Kings]] due to the extremely high concentration and variety of monuments of the [[Thracian culture]].

Srednogorie region stretches between the Sub-Balkan valleys in the north and the Rilo-Rhodope Massif in the south and from west to east includes the mountains [[Zavalska Planina]], [[Viskyar Mountain|Viskyar]], Lyulin, Vitosha, [[Plana Mountain|Plana]] and Sredna Gora. The largest of these, Sredna Gora, is 280&nbsp;km and reaches a maximum width of 50&nbsp;km.<ref name="Donchev 2004 107"/> Kraishte region covers the western parts of the Transitional geomorphological region and consists of two almost parallel mountain groups, Ruysko–Verilska and Konyavsko–Milevska, as well as numerous valleys.<ref>{{harvnb|Donchev|Karakashev|2004|p=114}}</ref>

The Upper Thracian Plain encompasses the middle valley of the river [[Maritsa]] and has a roughly triangular shape, situated between Sredna Gora in the north, the Rhodope Mountains in the south and Sakar Mountain in the east. The lowland is 180&nbsp;km long and up to 50&nbsp;km wide, spanning an area of 6,000&nbsp;km<sup>2</sup>.<ref>{{harvnb|Donchev|Karakashev|2004|p=117}}</ref> To the east are located the Burgas Plain, [[Svetiiliyski Heights]], [[Manastirski Heights]], [[Hisar Heights]], [[Bakadzhitsite]], Dervent Heights, and the low mountain ranges of Sakar and Strandzha.<ref>{{harvnb|Donchev|Karakashev|2004|p=121}}</ref>