Famous Buildings and Structures Prehistorical and Ancient The megalithic passage tomb atNewgrangein Ireland covers over an acre and was constructed around 3200B.C.Buried for centuries, the mound was rediscovered in 1699 and was restored starting in 1962. The tomb is extensively decorated with spiral and lozenge shapes. At the winter solstice, the rising sun shines down a long passage and lights up a cross-shaped chamber. Stonehenge,a massive circular megalithic monument on the Salisbury Plain in southern England, is the most famous of all prehistoric structures. Thought to have been built c. 2000B.C.,it may have been used as an astronomical instrument to measure solar and lunar movements. The Great Sphinxof Egypt, one of the wonders of ancient Egyptian architecture, adjoins thepyramids of Gizaand has a length of 240 ft. Built in the fourth dynasty, it is approximately 4,500 years old. A 10-year, $2.5 million restoration project was completed in 1998. Other Egyptian buildings of note include theTemples of Karnak,Edfu,andAbu Simbeland theTombs at Beni Hassan. The Parthenonof Greece, built on the Acropolisin Athens, was the chief temple to the goddess Athena. It was believed to have been completed by 438B.C.The present temple remained intact until the 5th centuryA.D.Today, though the Parthenonis in ruins, its majestic proportions are still discernible. Other great structures of the ancient Greek world were theTemples at Paestum(c. 540 and 420B.C.); the famous Erechtheum(c. 421–405B.C.), theTemple of Athena Nike(c. 426B.C.), and theOlympieum(begun in the 6th centuryB.C.) in Athens; theAthenian Treasuryat Delphi (c. 515B.C.); and theTheater at Epidaurus(c. 325B.C.). The Colosseum(Flavian Amphitheater) of Rome, the largest and most famous of the Roman amphitheaters, was opened for useA.D.80. Elliptical in shape, it consisted of three stories and an upper gallery, rebuilt in stone in its present form in the 3rd centuryA.D.It was principally used for gladiatorial combat and could seat between 40,000 and 50,000 spectators. The Pantheonat Rome, begun by Agrippa in 27B.C.as a temple, was rebuilt in its present circular form by Hadrian (A.D.118–128). Literally the Pantheonwas intended as a temple of “all the gods.” It is remarkable for its perfect preservation today, and has served continuously for 20 centuries as a place of worship. Famous Roman triumphal arches, built to commemorate major military victories, include theArch of Titus(c.A.D.80) and theArch of Constantine(c.A.D.315). Later European St. Mark's Cathedralin Venice (1063–1071), one of the great examples of Byzantine architecture, was begun in the 9th century. Partly destroyed by fire in 976, it was later rebuilt as a Byzantine edifice. Other famous examples of Byzantine architecture areSt. Sophiain Istanbul (532–537);San Vitalein Ravenna (542); andAssumption Cathedralin the Kremlin, Moscow (begun in 1475). The cathedral group at Pisa (1067–1173), one of the most celebrated groups of structures built in Romanesque style, consists of the cathedral, the cathedral's baptistery, and the campanile ( Leaning Tower). The campanile, a form of bell tower, is 180 ft high and now leans 13.5 ft out of the perpendicular. Other examples of Romanesque architecture include theVézelay Abbeyin France (1130) andDurham Cathedralin England. TheAlhambra(1248–1354), located in Granada, Spain, is universally esteemed as one of the greatest masterpieces of Muslim architecture. Designed as a palace and fortress for the Moorish monarchs of Granada, it is surrounded by a heavily fortified wall more than a mile in perimeter. The Tower of Londonis a group of buildings and towers covering 13 acres along the north bank of the Thames. The centralWhite Tower,begun in 1078 during the reign of William the Conqueror, was originally a fortress and royal residence, but was later used as a prison. TheBloody Toweris associated with Anne Boleyn and other notables. Westminster Abbey,in London, was begun in 1050 and completed in 1065. It was rebuilt and enlarged in several phases, beginning in 1245. With only two exceptions (Edward V and Edward VIII), every British monarch since William the Conqueror has been crowned in the abbey. Notre-Dame de Paris(begun in 1163), one of the great examples of Gothic architecture, is a twin-towered church with a steeple over the crossing and immense flying buttresses supporting the masonry at the rear of the church. Other famous Gothic structures are Chartres Cathedral(France; 12th century);Sainte-Chapelle(Paris, France; 1246–1248);Reims Cathedral(France; 13th–14th centuries; rebuilt after its almost complete destruction in World War I);Rouen Cathedral(France; 13th–16th centuries);Salisbury Cathedral(England; 1220–1260);York Minster, or theCathedral of St.