The Grey Cairns of Camster are two large Neolithic chambered cairns in the Highland region of Scotland. They are among the oldest buildings in Scotland, dating to about 5,000 years ago. The cairns demonstrate the complexity of Neolithic architecture, with central burial chambers accessed through narrow passages from the outside. They were excavated and restored by Historic Scotland in the late 20th century and are open to the public.
The cairns, which are considered to be examples of the Orkney-Cromarty type of chambered cairn, were constructed in the third or fourth millennium BC in a desolate stretch of boggy peat-covered moorland in the Flow Country of Caithness. They consist of two structures standing 180 m apart, known as Camster Round and Camster Long. A third cairn, located about 120 metres away from Camster Round, is not considered to be part of the grouping. Although the surrounding countryside is now inhospitable and sparsely inhabited, during the Stone Age it was fertile farming land and only became covered in peat during the Bronze Age.
Camster Long is a 60 m long cairn with 'horns' at each end. The two chambers appear to have originally been constructed within separate round cairns, which were only later incorporated into a single long cairn for unknown reasons.
Camster Round is, as the name suggests, a circular cairn; it measures 18 metres in diameter by 3.7 metres high. It is virtually intact with a high vaulted chamber at its centre, accessed from a passage 6 metres long and 0.8 metres high at the east-south-east side of the cairn. The passage appears to have been deliberately put out of use by blocking it up with stones piled up to the height of its roof.References:
The Mosque–Cathedral of Córdoba, also known as the Great Mosque of Córdoba and the Mezquita is regarded as one of the most accomplished monuments of Moorish architecture.
According to a traditional account, a small Visigoth church, the Catholic Basilica of Saint Vincent of Lérins, originally stood on the site. In 784 Abd al-Rahman I ordered construction of the Great Mosque, which was considerably expanded by later Muslim rulers. The mosque underwent numerous subsequent changes: Abd al-Rahman II ordered a new minaret, while in 961 Al-Hakam II enlarged the building and enriched the Mihrab. The last of such reforms was carried out by Almanzor in 987. It was connected to the Caliph"s palace by a raised walkway, mosques within the palaces being the tradition for previous Islamic rulers – as well as Christian Kings who built their palaces adjacent to churches. The Mezquita reached its current dimensions in 987 with the completion of the outer naves and courtyard.
In 1236, Córdoba was conquered by King Ferdinand III of Castile, and the centre of the mosque was converted into a Catholic cathedral. Alfonso X oversaw the construction of the Villaviciosa Chapel and the Royal Chapel within the mosque. The kings who followed added further Christian features, such as King Henry II rebuilding the chapel in the 14th century. The minaret of the mosque was also converted to the bell tower of the cathedral. It was adorned with Santiago de Compostela"s captured cathedral bells. Following a windstorm in 1589, the former minaret was further reinforced by encasing it within a new structure.
The most significant alteration was the building of a Renaissance cathedral nave in the middle of the expansive structure. The insertion was constructed by permission of Charles V, king of Castile and Aragon. Artisans and architects continued to add to the existing structure until the late 18th century.
The building"s floor plan is seen to be parallel to some of the earliest mosques built from the very beginning of Islam. It had a rectangular prayer hall with aisles arranged perpendicular to the qibla, the direction towards which Muslims pray. The prayer hall was large and flat, with timber ceilings held up by arches of horseshoe-like appearance.
In planning the mosque, the architects incorporated a number of Roman columns with choice capitals. Some of the columns were already in the Gothic structure; others were sent from various regions of Iberia as presents from the governors of provinces. Ivory, jasper, porphyry, gold, silver, copper, and brass were used in the decorations. Marvellous mosaics and azulejos were designed. Later, the immense temple embodied all the styles of Morisco architecture into one composition.
The building is most notable for its arcaded hypostyle hall, with 856 columns of jasper, onyx, marble, granite and porphyry. These were made from pieces of the Roman temple that had occupied the site previously, as well as other Roman buildings, such as the Mérida amphitheatre. The double arches were an innovation, permitting higher ceilings than would otherwise be possible with relatively low columns. The double arches consist of a lower horseshoe arch and an upper semi-circular arch.