OLD BULGARIAN BORDER RIDGE "ERKESIA"
The medieval border ridge is long 130 km. It started at the rand of Burgas Lake - nowadays village Gorno Ezerovo and crossed to the west - southwest the lands of present municipalities Kameno and Sredets
The ridge is best preserved in height and as a moat between the village Rusokastro and Debelt, localized on 20 km southwest from Burgas:
5 km along the republican road 79 direction Burgas-Lesovo border crossing to Turkey, from the junction in Konstantinovo /old name Novoseltsi/ drive further 15 km to Rusokastro.
The border ridge continues through regions Yambol and Haskovo and reaches the bank of Maritsa River in South.
The biggest old Bulgarian fortification construction situated south of the Balkan Mountain, it was built in the early 9th century to guard the Bulgarian border. Its length is 130 km starting northeast of the village Debelt, reaching Maritsa River to the south. The ridge has marked the border between Bulgaria and Byzantium, set with the signing of the peace treaty between the Khan Omurtag and Emperor Leo V the Armenian in 815 - 816. The actual construction and operation of Erkesia border ridge is related to the Bulgarian-Byzantine wars in 812-813 during the reign of Khan Krum. In the village Rusokasro there is an old song preserved that tells of the Bulgarian ruler visit and his meeting with the builders of Erkesia, who then inhabited the fortress Rusokastron.
Old Bulgarian earth ridge represent a unique combination of trench with shaft (embankment), the total width varies from 10 to 40 meters depending on their strategic purpose. The width proportion of the trench and embankment are usually 1:1. The depth of the trench is about 3 meters and the embankment is about 3-4 m in height.
Cultural monument of national importance.
Conducted archaeological surveys and urgent safety activities.
Erkesia border ridge is 130 km in length, starting northeast of the village Debelt and reaching Maritsa River to the south.