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Star fort - Europe A star fort, or trace italienne, is a fortification in the style that evolved during the age of gunpowder, when cannon came to dominate the battlefield, and was first seen in the mid-15th century in Italy. Passive ring-shaped (enceinte) fortifications of the Medieval era proved vulnerable to damage or destruction by cannon fire, when it could be directed from outside against a perpendicular masonry wall. In addition, an attacking force that could get close to the wall was able to conduct undermining operations in relative safety, as the defenders could not shoot at them from nearby walls. In contrast, the star fortress was a very flat structure composed of many triangular bastions, specifically designed to cover each other, and a ditch. Further structures, such as ravelins, hornworks or crownworks, and detached forts could be added to create a complex symmetrical structure. File:Fortbourtange.jpg| File:Map_of_Geneva_in_1841.jpg| File:Olomouc_map_1757.jpg| File:Palmanova1600.jpg| File:Coevorden.jpg| Star fortifications were further developed in the late 15th and early 16th centuries primarily in response to the French invasion of the Italian Peninsula. The French Army was equipped with new cannon and bombards that were easily able to destroy traditional fortifications built in the Middle Ages. In order to counteract the power of the new weapons, defensive walls were made lower and thicker. They were built of many materials, usually earth and brick, as brick does not shatter on impact from a cannonball as does stone. Another important design modification were the bastions that characterized the new fortresses. In order to improve the defense of the fortress, covering fire had to be provided, often from multiple angles. The result was the development of star-shaped fortresses. ==Triangula Bastion history – Riga, Latvia== From its foundation in 1201 Riga always had fortification wall system surrounding it. In the 16th and 17th centuries a new type of defensive system was developed in Riga to protect town against artillery attack. The territory of the present Old Riga was surrounded with an earthen rampart. Positioned at the corners of the rampart and the major gates were projecting polygonal fortifications – bastions. In the moat in front of these, artificial fortified triangular islands – ravelins – were built. A separate fortress, the Citadel on the bank of the Daugava downstream from the castle, provided additional protection. All this made Riga one of the strongest fortified centres on the eastern shore of Baltic Sea. Over the course of time, the fortification systems were improved: the outer walls of the defenses were faced with stone blocks, the moat was broadened and forward defences were added in front of the rampart. As firearms developed, the fortifications gradually lost their importance and began to hinder urban development. Between 1857 and 1864 the wall was taken down. Only part of the moat was preserved to form the city canal, and an artificial mound, called Bastejkalns, was thrown up at the site of the former Sand Bastion. File:Old_Riga.jpg| File:Old_Riga_2.jpg| The Triangula Bastion, the smallest though highest of the bastions, was reconstructed in 1727. The fortification was pentagonal in plan, open on the side facing the town. The width of the Bastion at the city rampart reached 61 metres, while the distance from rampart to the outermost point 35 meters. The bastion wall was 7 – 8 metres high, built at an angle of 50 - 70 degrees. It was faced with blocks of pink and grey dolomite. Behind decorative blocks, the 2,1 metres thick wall itself was built of rough grey dolomite. Inside the fortified area there was another, inner wall repeating the shape of the outer wall and separated from it by a distance of 5 – 11 metres. The space between the walls was filled with sand. Triangula Bastion lives today When a group of businessmen under the company name Speks-R started building in 2000 they found and made most profound investigation of old fortification walls. The AIG Company excavated the Triangula Bastion under the direction of the Museum of the History of Riga and Navigation and Martins Lusens. As a result the Triangula Bastion is the most profoundly investigated part of Riga’s 17th–19th-century fortification system which was preserved inside the new building. File:16_Century_Wall.jpg| File:bastion_excavation.jpg| File:16_Century_wall_in_21_Century_building.jpg| When a new glass building was built, there were strong opinions about the building's architectural style. For the people who had spent 70 years under the rule of Soviet Union and were not used to modern art and architecture, the Triangula Bastion building was shocking. But architectural revolution was inevitable even for those who at that time did not understand it. File:Krastmala.JPG| File:Triangula Bastion 1.JPG| File:TB_winter.jpg| The building has huge terraces with views of riverside which you can only enjoy two ways: 1. if you are a president of Latvia and you live in Riga Palace 2. if you are standing on the terraces of Triangula Bastion. File:Triangula_view.JPG| File:Triangula_view_2.jpg| File:Terrace_Sun.JPG| For more than five years the terraces were not accessible for people. The views from the terraces were hidden but as time passed and as Riga becomes more friendly and attractive for tourists, management of the Triangula Bastion decided to open the terraces for tourists. File:Marathon_1.JPG| File:Marathon_2.JPG| Today you can enjoy Daugava river views of Riga from the terraces of Triangula Bastion. Nearly all Riga city celebrations takes place on the river bank of Daugava, the place where Triangula Bastion stands. File:TB_Staro_Riga.jpg| File:Staro_Riga_Just.jpg| File:Bastion_Ligo.JPG| File:Bastion_Ligo_2.JPG| File:Bastion_Ligo_3.JPG| 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Triangula Bastion」の詳細全文を読む スポンサード リンク
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