Toompea Castle is situated on the steep limestone hill in the central part of Tallinn. The first wooden castle is believed to have been built on the hill in either the 10th or 11th century by residents of the ancient Estonian county of Rävala. It was probably one of the first inhabited areas of what later became Tallinn. In 1219, the castle was taken over by Danish crusaders - led by Valdemar II. According to a legend very popular among Danes, the very first flag of Denmark (Dannebrog) fell from the sky during a critical stage of the Battle of Lyndanisse, fought near the castle, resulting in Danish victory over Estonians. The current castle is mainly constructed in the 13th and 14th centuries.
The castle is one of the most potent symbols of the reigning power, which over the centuries has been conquered by various nations. According to the Altmark peace treaty of 1629, Estonian territories went to the king of Sweden. In 1583–1589 a new ceremonial building, the State Hall building, was erected on Toompea. It was located against the western wall between Tall Hermann tower and the convent building.
In 1710 the ownership of Toompea went from the Swedes to the Russian Czarist Empire. The Russian Empress Catherine the Great ordered the construction of the Estonian Government Administration building in the east side of the fortress; it was completed in 1773.
On 24 February 1918, Estonia became an independent state. From 1920 until 1922, according to the plans of the architects Eugen Habermann and Herbert Johansen, the building of the Parliament (Riigikogu) was built in the castle courtyard. The expressionist design of the building makes it unique among the parliament buildings of the world. In 1935, the palatial south wing was built on the south side, copying the style of the Government Administration building, and the Governor's Garden was laid out in appropriate design.
The Toompea castle and the surrounding old town are is one of the best preserved medieval cities in Europe. Nineteen of the original sixty six defense towers are survived. The old town is in the list of UNESCO World Heritage Sites. The castle is open to the public with no charge. There are also guided services available.
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.