Since before recorded history, humans have left their legacies on the Earth in the form of architectural structures. These have ranged in scope from mounds and simple markers to spectacular feats of construction. Many have been destroyed by war or natural disasters, but some survive as ruins, reconstructed replicas or meticulously-maintained structures.
Stonehenge is a ring of standing stones, built by prehistoric peoples during the Neolithic and Bronze ages. Rising out of the countryside near what is now Wiltshire, England, this UNESCO World Heritage Site is considered to be a cultural icon. The stones, partially buried beneath the ground, are roughly thirteen feet high, seven feet wide and weigh approximately 25 tons. This circular monument sits above several hundred burial mounds which contain human remains dating back to 3000-2500 BC. Construction of the site appears to have begun with an earthen embankment and ditch around 3100 BC, while the stones are believed to have been placed there between 2400 and 2200 BC.
An iconic symbol of the Roman Empire, the Colosseum is one of Rome's major tourist attractions. The oval amphitheater, located in the city center, was built and improved upon between 72 and 96 AD during the Flavian dynasty, a group of three emperors including Vespasian, Titus and Domitian. Now partially ruined due to human destruction and natural disasters, this impressive structure of concrete and sand has never been surpassed in size. The Colosseum is the largest amphitheater ever built, and once hosted audiences of 50,000 to 80,000 people. Spectators enjoyed events that included staged animal hunts, executions, historical re-enactments, mythological dramas, and gladiator battles. During the early medieval era, the Colosseum was later repurposed for housing, religious services, workshops, fortifications, and eventually used as a quarry for other building projects.
5. Catacombs of Kom el Shoqafa
The catacombs of Kom el Shoqafa are located in the western necropolis of Alexandria, Egypt. Constructed during the reign of the Antonine emperors in the second century AD, the catacombs consist of tombs carved into three levels solid rock, although the lowest level is currently submerged by groundwater. These tombs contain statues, friezes and other artifacts showing the influence of Roman, Greek and Egyptian cultures. Originally accessible by a circular staircase through an access shaft, the catacombs were used as a burial site from the second to the fourth centuries AD. On the first level, the Hall of Caracalla houses the bones of Christians who were massacred by the emperor of the same name in 215 AD.
"Kom El Shoqafa" means "mound of shards", named for the heaps of broken terra cotta jars and other objects found by archaeologists during excavation of this site. It is believed that ancient visitors to the tombs brought food and wine and, due to superstition, broke the containers and left them in the catacombs rather than bring them home again.
4. Great Wall of China
The Great Wall of China spans from Dandong to Lop Lake, in an arc that runs from east to west, roughly parallel to ancient China's northern border. Construction began in multiple locations in the seventh century BC; these walls were later joined together and fortified. The wall has been destroyed, rebuilt and maintained numerous times over the centuries, with the majority of the existing structure dating back to the Ming Dynasty of the fourteenth to seventeenth centuries. Built to withstand raids and invasions by the Eurasian nomads, the Great Wall was built from stone, brick, wood, and packed earth, among other materials. In areas most vulnerable to attack, fortifications were enhanced with military housing and stations, watch towers, and smoke-signalling stations. The wall was also utilized for emigration control, commerce, and trade regulation.
3. Porcelain Tower of Nanjing
The Porcelain Tower of Nanjing was a fifteenth century pagoda, built during the Ming Dynasty on the banks of the Qinhuai River. One of the tallest buildings in China at the time of its completion, the tower rose nine stories high to a height of 260 feet. A 184-step spiral staircase rose through the center of the pagoda, and the roof was crowned with a golden pineapple. The outside of the tower consisted of white porcelain bricks which reflected the sun's rays in dazzling fashion. At night, lamps were hung on the outside for further illumination. Landscapes, flowers, animals and Buddhist images adorned the sides of the tower through decorative stonework and glazes. Considered by some to be one of the Seven Wonders of the World, the Porcelain Tower of Nanjing was a well-known landmark and cultural icon for hundreds of years.
Although there had been plans to increase its height, the tower was destroyed during the Taiping rebellion of the 1850s. The rubble was used for other building projects, and the site was eventually abandoned. However, in 2010 a private individual donated one billion yuan (approximately 156 million US dollars) to the city of Nanjing to finance a reconstruction.
2. Hagia Sophia
Hagia Sophia is a Greek Orthodox basilica in Istanbul, Turkey. Commissioned by Emperor Justinian I and completed in 537 AD, Hagia Sophia was the largest cathedral in the world for almost 1,000 years. With its characteristic massive dome, this masterpiece of Byzantine architecture also contains a vast array of decorative influences characterizing the historical and cultural changes in the region. Hagia Sophia served as the Roman Empire's first Christian Cathedral until the Ottoman Empire conquered the city in 1453. Although much of the city was left in disrepair, Hagia Sophia was maintained and converted into a mosque. It served as the principal mosque of the city for almost two hundred years. In 1935, the building was decommissioned as a church and converted into a museum.
1. Leaning Tower of Pisa
The leaning tower of Pisa is a freestanding bell tower near the cathedral in the city of Pisa, Italy. The building began to tilt almost immediately during its construction in the twelfth century, caused by soft ground and poor foundation engineering. Construction continued into the fourteenth century, and the unintentional tilt gradually increased. At its apex, the tower leaned at an angle of five and a half degrees, with the top of the tower displaced more than eighteen feet from the center. The tilt was partially corrected and the building was stabilized by preservation architects in 2001.