Editing Geography of Bulgaria (section)

== Topography ==
[[File:MontañasDeBulgaria.svg|thumb|250px|alt=a map|Topographic map of Bulgaria highlighting the main mountain ranges]]
The [[Terrain|relief]] of Bulgaria is varied. In the relatively small territory of the country there are extensive lowlands, plains, hills, low and high mountains, many valleys and deep gorges.<ref name="donchev25">{{harvnb|Donchev|Karakashev|2004|p=25}}</ref> The main characteristic of Bulgaria's topography is four alternating bands of high and low terrain that extend east to west across the country. From north to south, those bands, called [[geomorphological]] regions, are the [[Danubian Plain (Bulgaria)|Danubian Plain]], the [[Balkan Mountains]], the Transitional region and the [[Rila|Rilo]]-[[Rhodope Mountains|Rhodope]] region. The easternmost sections near the [[Black Sea]] are hilly, but they gradually gain height to the west until the westernmost part of the country is entirely high ground.<ref name="donchev25"/>

Table, showing the distribution of the height zones in Bulgaria:<ref name="donchev26">{{harvnb|Donchev|Karakashev|2004|p=26}}</ref>
{|  class="wikitable"
|-
! Height zones
! Height (m)
! Area (km<sup>2</sup>)
! Area (%)
|-
| [[Lowland]]s || 0–200 || 34,858 || 31.42
|-
| Hills || 200–600 || 45,516 || 41.00
|-
| Low mountains || 600–1000 || 16,918 || 15.24
|-
| Medium-high mountains || 1000–1600 || 10,904 || 9.82
|-
| High mountains || 1600–2925 || 2,798 || 2.52
|-
|}
More than two-thirds of the country is plains, plateaus, or hilly land at an altitude less than 600&nbsp;m. Plains (below 200&nbsp;m) make up 31% of the land, plateaus and hills (200 to 600&nbsp;m) 41%, low mountains (600 to 1,000&nbsp;m) 10%, medium-high mountains (1,000 to 1,500&nbsp;m) 10%, and high mountains (over 1,500&nbsp;m) 3%.<ref name="donchev26"/> The average altitude of Bulgaria is 470&nbsp;m.

The contemporary relief of Bulgaria is a result of continuous geological evolution. The Bulgarian lands were often submerged by ancient seas and lakes, some land layers rose others sank. [[Volcanic eruption]]s were common both on land and in the water basins.<ref name="donchev26"/> All three main groups of rocks, [[magmatic rocks|magmatic]], [[sedimentary]] and [[metamorphic]], are found in the country.<ref name="donchev25"/> The oldest rock formations in Bulgaria date from the [[Precambrian]] period than 500&nbsp;million years ago. During the [[Archean]], [[Proterozoic]] and [[Paleozoic]] eras (4.0&nbsp;billion to 252&nbsp;million years ago) the magmatic rocks were formed. Throughout most of that period the only land areas were Rila, Pirin and the western Rhodope Mountains.<ref name="donchev27">{{harvnb|Donchev|Karakashev|2004|p=27}}</ref> The [[Mesozoic]] era (252&nbsp;million to 66&nbsp;million years ago) saw the beginning of the [[Alpine orogeny]] that has formed the mountain ranges of the [[Alpide belt]], including the Balkan Mountains and [[Sredna Gora]].<ref name="donchev27"/> The [[Cenozoic]] era (since 66&nbsp;million years ago) is characterized with active tectonic processes, the definitive formation of the Balkan Mountains, the formation of [[graben]]s and [[Horst (geology)|horsts]] in Rila, Pirin and Kraishte region.<ref name="donchev27"/>

Examples of [[rock formations in Bulgaria]]:
<gallery mode="packed">
File:Белоградчишки скали 07.JPG|[[Belogradchik Rocks]], western Balkan Mountains
File:Devetashka pestera lqto 2009 1.JPG|[[Devetashka cave]], Pre-Balkan
File:Bulgarian Pyramid.jpg|[[Melnik Earth Pyramids]], Pirin Mountains
File:Bulgaria-Pobiti Kamani-04.jpg|[[Pobiti Kamani]], Danubian Plain
File:Слънчеви лъчи.JPG|[[Marvelous Bridges]], Rhodope Mountains
</gallery>
[[Exogeny|Exogenous processes]] such as [[weathering]], [[erosion]] and [[sedimentation]] have an important impact on modelling the land surface and creating rock formations.<ref>{{harvnb|Donchev|Karakashev|2004|p=28}}</ref> The exogenous processes have formed [[stone rivers]] in Vitosha; [[scree]]s in the Balkan Mountains, Rila and Pirin; [[Hoodoo (geology)|earth pyramids]] in [[Melnik, Bulgaria|Melnik]], [[Stob (village)|Stob]] and Katina; [[landslide]]s, mainly along the Danube banks and the northern Black Sea coast; [[fluvial terrace]]s; [[Aeolian processes|aeolian forms]], such as [[dune]]s; [[karst]] forms, including numerous caves, [[sinkhole]]s, [[ponor]]s, etc.<ref>{{harvnb|Donchev|Karakashev|2004|p=29}}</ref>

=== Danubian Plain ===
{{multiple image
 | footer = ''Left:'' Fields in the Danubian Plain between [[Veliko Tarnovo]] and [[Ruse, Bulgaria|Ruse]]. ''Right:'' The village of [[Cherven, Ruse Province|Cherven]], Ruse Province
 | image1 = 20140624 between Veliko Tarnovo and Rousse 07.jpg
 | width1= 290
 | alt1 = A field in a plain
 | caption1 = 
 | image2 = Village of Cherven.jpg
 | width2= 250
 | alt2 = A village
 | caption2 = 
 }}
The [[Danubian Plain (Bulgaria)|Danubian Plain]] encompasses the Moesian plate and extends from the river Timok in the west to the Black Sea in the east and from the river [[Danube]] in the north to the Balkan Mountains in the south, covering 31,520&nbsp;km<sup>2</sup>, or almost 1/3 of Bulgaria's total area.<ref>{{harvnb|Donchev|Karakashev|2004|pp=34, 92}}</ref> Its width varies from 25 to 30&nbsp;km in the west to 120&nbsp;km in the east. The highest point is Tarnov Dyal (502&nbsp;m) on the [[Shumen Plateau]]; the average altitude is 178&nbsp;m.<ref name="donchev92">{{harvnb|Donchev|Karakashev|2004|p=92}}</ref> As a result of the rock weathering processes the relief is uneven with fertile [[alluvial plain]]s along the Danube (Vidinska, Chernopolska, [[Zlatia (region)|Zlatia]], Belenska, Pobrezhie, Aidemirska), and hilly terrain in the remaining area, including plateaus in the east. The altitude rises from west to east. The valleys of the rivers [[Vit (river)|Vit]] and [[Yantra River|Yantra]] divide the Danubian Plain into three parts&nbsp;– western, central and eastern.<ref name="donchev92"/> The topography of the plain is characterized with hilly heights and plateaus. Most of the heights and all plateaus are situated in the eastern parts. There are 14 [[basalt]] mounds between [[Svishtov]] and the village of [[Dragomirovo, Veliko Tarnovo Province|Dragomirovo]].<ref name="donchev34">{{harvnb|Donchev|Karakashev|2004|p=34}}</ref>

The predominant soil types are [[loess]] in the north, reaching a depth of up to 100&nbsp;m at the banks of the Danube, and [[chernozem]] in the south.<ref name="donchev93">{{harvnb|Donchev|Karakashev|2004|p=93}}</ref> The climate is [[temperate]]. The flat relief and the openness of plain to the north facilitate arrival of moist air masses in spring, summer and autumn. In winter the Danubian Plain falls under the influence of the Eastern European anticyclone, which brings cold Arctic air masses.<ref name="donchev93"/> The mean temperature in January is −1&nbsp;°C and in July is 24&nbsp;°C, making it the geomorphological region with the highest average annual amplitude in Bulgaria&nbsp;– 25&nbsp;°C.<ref name="donchev93"/>

=== Balkan Mountains ===
[[File:Panorama Ray hut & Botev peak.jpg|thumb|right|540px|alt=a mountain|A view of the central Balkan Mountains]]
The [[Balkan Mountains]] range is a geological continuation of the [[Carpathian Mountains]], forming part of the [[Alpine-Himalayan orogenic belt]]. This region is subdivided into two geomorphological units, the Pre-Balkan and the Balkan Mountains, also known in Bulgarian as ''Стара Планина''&nbsp;– "Old Mountain". Their average altitude is 370&nbsp;m and 735&nbsp;m, respectively.<ref name="donchev34"/> Its total area is 26,720&nbsp;km<sup>2</sup>, of them the Pre-Balkan spans 15,730&nbsp;km<sup>2</sup> and the Balkan Mountains&nbsp;– almost 11,000&nbsp;km<sup>2</sup>.<ref name="donchev100">{{harvnb|Donchev|Karakashev|2004|p=100}}</ref> The mountain range stretches from the valley of the river Timok in the west to [[Cape Emine]] at the Black Sea coast in the east, spanning a length of 555&nbsp;km and width between 20 and 70&nbsp;km.<ref name="donchev99">{{harvnb|Donchev|Karakashev|2004|p=99}}</ref> The Balkan Mountains are divided into western, central and eastern part by the [[Zlatitsa Pass|Zlatitsa]] and [[Vratnik Pass (Bulgaria)|Vratnik Pass]]es.<ref name="donchev100"/> The range is highest in its central part, which includes [[Botev Peak]] at 2,376&nbsp;m; the altitude drops slowly to the east until it reaches the sea. The relief is varied, with many mountain passes, gorges and landforms. The southern slopes are steeper than the northern.<ref name="donchev34"/> For the most part the Balkan Range defines the most important watershed in Bulgaria with rivers draining north to the Danube or south to the river [[Maritsa]] and the [[Aegean Sea]]. Several rivers in the east drain directly into the Black Sea. In the west, the river [[Iskar (river)|Iskar]] forms a [[Iskar Gorge|65-km long gorge]] that runs north through the mountains.<ref name="donchev100"/>

=== 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>

=== Rilo-Rhodope region ===
[[File:Pirin panorama crop 1.JPG|thumb|right|540px|alt=a mountain|A view of Pirin]]
The Rilo-Rhodope geomorphological region covers the south-western regions of Bulgaria and includes the [[Rhodope Mountains]], [[Rila]], [[Pirin]], [[Osogovo]], [[Vlahina]], [[Maleshevo Mountain|Maleshevo]], [[Ograzhden (mountain)|Ograzhden]], [[Slavyanka (mountain)|Slavyanka]] and [[Belasitsa]], as well as the valleys of the rivers [[Struma (river)|Struma]] and [[Nestos (river)|Mesta]].<ref name="donchev35"/> The Rhodopes are the most extensive mountain range in Bulgaria, spanning an area of 14,730&nbsp;km<sup>2</sup> with an average altitude of 785&nbsp;m, characterized with gentle and densely forested slopes. Their length from west to east is 249&nbsp;km and reach width of 100&nbsp;km.<ref>{{harvnb|Donchev|Karakashev|2004|p=132}}</ref> The altitude decreases from west to east.<ref name="donchev35"/>

To the west are located Rila and Pirin, Bulgaria's two highest mountains. Rila includes [[Mount Musala]], whose 2,925&nbsp;m peak is the highest in the [[Balkan Peninsula]], while Pirin's highest peak [[Vihren]] at 2,915&nbsp;m is the third-highest in the Balkans. Both Rila and Pirin have rocky peaks, stony slopes, extensive [[Alpine zone]] and hundreds [[glacial lake]]s.<ref>{{harvnb|Donchev|Karakashev|2004|pp=35–36}}</ref> Further west is the Osogovo–Belasitsa mountain group along the border with North Macedonia, whose highest peak is [[Ruen (peak)|Ruen]] in Osogovo at 2,251&nbsp;m.<ref>{{harvnb|Donchev|Karakashev|2004|p=36}}</ref>

=== Black Sea coast ===
[[File:Ropotamo beach.jpg|thumb|right|250px|alt=coastline|The coastline at the river [[Ropotamo]]]]
The [[Bulgarian Black Sea Coast]] has a total length of 378&nbsp;km from [[Durankulak]] in the north to the mouth of the river [[Rezovska]] in the south.<ref name="donchev146">{{harvnb|Donchev|Karakashev|2004|p=146}}</ref> The northernmost section between the Bulgarian-Romanian border to [[Shabla]] has extensive sandy beaches and several coastal lakes, then the elevation rises as the coast reaches Cape [[Kaliakra]], with 70&nbsp;m high vertical cliffs. Near [[Balchik]] and [[Kavarna]] the limestone rocky coast is cut by wooded valleys. The landscape around the coast resorts of [[Albena]] and [[Golden Sands]] is hilly, with a clearly expressed land                                                     slides. Dense forests at the mouth of the river [[Batova]] mark the beginning of Frangensko plateau. South of [[Varna, Bulgaria|Varna]] the coastline is densely wooded, especially at the alluvial longose groves of the [[Kamchia Biosphere Reserve]]. [[Cape Emine]] marks the end of the Balkan Mountain and divides the Bulgarian Black Sea coast in northern and southern parts. The southern section has wide and long beaches, with a number of small bays and headlands.<ref name="donchev146"/> All Bulgarian Black Sea islands are situated in the southern coast: [[St. Anastasia Island|St. Anastasia]], [[St. Cyricus Island|St. Cyricus]], [[St. Ivan Island|St. Ivan]], [[Saint Peter Island (Bulgaria)|St. Peter]] and [[St. Thomas Island|St. Thomas]]. Sandy beaches occupy 34% of the Bulgarian coastline.<ref>{{harvnb|Donchev|Karakashev|2004|p=147}}</ref> The two most important gulf are the [[Gulf of Varna]] in the north and the [[Gulf of Burgas]] in the south, which is the largest in the Bulgarian Black Sea coast.<ref name="donchev146"/>