Posts Tagged With: engineering
Right or Left? That was our choice when we arrived at Base Camp—my nickname for the concrete entryway, lined with small shops and a ticket booth—at the Great Wall of China’s Badaling section, 40 miles northwest of Beijing.
Only select sections of the crumbling Great Wall have been fully or partially restored. Badaling is one of the best. It’s also closest to the country’s bustling capital. As such, it’s the most crowded, especially when we were there—during October’s National Day Holiday, when everyone in the country goes on vacation for a week and makes a beeline for Beijing and the Great Wall. During peak times (i.e. holidays), it’s estimated that 70,000 people per day visit Badaling.
Before traveling to China, I’d watched a tv show documenting the Great Wall’s history. In the 3rd century BC, during what’s known as the Warring States period, Qin Shi Huang’s army defeated armies from the other 6 kingdom states in what is now China. After crowning himself emperor of the now unified country, he ordered most fortifications between the states demolished. Some walls he kept and joined together in a single system to protect his empire from barbarians in the north.
Using mostly packed earth and rocks, almost a million peasants, criminals, soldiers, disgraced nobles and unemployed intellectuals slaved for ten years to construct a wall that stretched 3,100 miles. It’s estimated that 400,000 of these laborers died during construction, and many were buried in the wall, giving rise to its nickname: the world’s largest cemetery.
Over the years, there were various accounts of the wall’s efficacy. As dynasties came and went, it was either repaired or neglected. It kept out some invaders but not others such as Mongol Genghis Khan. Around 1206AD, his grandson Kublai Khan broke through, conquered China and created the Yuan Dynasty, stationing soldiers along the wall to protect merchants and caravans traveling along profitable Silk-Road trade routes.
The year 1368 saw the defeat of the Mongols and the establishment of the Ming Dynasty, which put a great deal of effort into fixing and strengthening the wall, building fortresses, steps, watchtowers and gates; employing skilled laborers; using bricks handmade of granite and limestone; and turning it into the fortification we know today (note: they added sticky-rice flour to the mortar, and although many bricks disintegrated, the mortar is still holding strong, leaving a pattern of holes where bricks used to be). The series of 25,000 towers built less than 500 feet apart and 30-40 feet high enabled troops garrisoned at each tower to see each other’s smoke signals, lanterns, flags and beacon fires and be ready to fight the enemy when and where he should appear.
In the mid 17th century, the Manchus broke through the wall, precipitating the fall of the Ming and beginning of the Qing Dynasty, which lasted until 1912.
Surprisingly, the Wall is not just one wall, but a series of walls, some running parallel or perpendicular to each other. At one time these walls slithered like giant snakes from the Yalu River in the west, through the Gobi Desert, along mountain ridges and sixty-six feet into the sea (so that raiders could not ride their horses around the end) for an estimated length of 5,500 miles (actual 13,170.7 miles, if you count all the branches). Many parts are now in ruins.
So, back to our choice. The left side, we were told, was a more difficult climb but with fewer people. No longer energetic youngsters, we opted for the easier Right side and were grateful for the railing on the steeper sections. Make no mistake—climbing the Great Wall is no walk in the park. There are steps—lots of them, and I noticed many of the younger Chinese huffing and puffing along with me as they pulled themselves up by the railing.
I could easily imagine soldiers running up and down these steps, using the nine-to-twelve-foot-wide top of the wall as a transportation corridor from tower to tower, firing canons and aiming their crossbows through the narrow battlement openings at the enemy below.
The crowds didn’t bother us. We rather enjoyed climbing with the Chinese tourists. Perhaps it was because they were on holiday and in a good mood, but they were courteous and friendly, many asking to take pictures with us. When I asked our guide about this later, she said that when they go back home, they’ll show off their foreigner “friends (us).” We’ll be famous in little villages all over China.
Can you really see the Great Wall from the moon? Well, not with the naked eye. It’s long enough, but not wide enough, says an astronomer friend. But photographs and radar imagery taken from a low-earth orbit do show the world’s longest defense fortification—one of the Seven Wonders of the World—snaking like a massive Chinese dragon across the desert, grasslands and mountaintops of China, enthralling us still.
Colorful ripples reflect our boat’s passage under and past this remarkable color-and-pattern-changing bridge on the Yangtze River.
Remind you of anything?
I wanted to climb the steps, but it was not allowed, and a guard stood by to ensure everyone followed the rules. Still, the idea of climbing on the giant edifices tugged at me just as it does a child who steps into an enchanting playground. And that’s what this place looked like—a playground filled with odd-shaped structures that begged to be climbed.
In reality, though, we were at Jantar Mantar—an astronomical observatory built by Maharaja Sawai Jai Singh, a soldier, scholar and ruler with a lifelong interest in math and astronomy. He founded the city of Jaipur in the 1720s and built five Jantar Mantar observatories in northern India.
Jantar Mantar means “instruments for calculation,” or “magical calculations.” The Jaipur observatory consists of 18 devices for measuring time, predicting eclipses, observing planet orbits; calculating the lunar calendar and predicting the start of the monsoon season. It’s main purpose, though, seems to have been casting horoscopes, which require a precise knowledge of the positions of the sun, moon, planets and stars at the moment of birth.
The largest instrument (with steps leading to its top) is a sundial 27 meters high, its shadow carefully plotted to tell the time of day to an accuracy of about two seconds. You can see the shadow moving at 1 millimeter per second, or roughly the width of a hand (6mm) every minute.
Influenced by the Islamic school of astronomy, Jai Singh also incorporated elements of early Greek and Persian observatories into his designs. The Jantar Mantars, however, are more complex, on a greater scale, and contain some completely unique designs and functions.
They were made almost entirely of masonry, with some engraved metal rings and plates set into masonry foundations, and they were built large because the larger the scale, the more accurate the measurements. Once finished, they could not be corrected or improved, and observations were limited to those involving the positions and motions of heavenly bodies that are visible to the naked eye.
Over the years, they’ve been restored from time to time—partly because they are tourist attractions, but also to keep them useful and scientifically authentic. Local astronomers still use them to predict the weather for farmers (although the accuracy is questionable), and students of astronomy and Vedic astrology are required to take some of their lessons at the observatories.
Because of their size and inflexibility, the Jantar Mantars were obsolete even before they were constructed and were soon replaced by smaller machined brass instruments and telescopes that proved more useful and accurate. Still, they are amazing reminders of ancient innovation and man’s quest to understand the universe.
Rong Gao (Dragon Bridge), Da Nang, Vietnam. Built in 2013 and designed by U.S. engineers, this dragon breathes fire and hissing smoke (water mist) each weekend after sunset. Now that I’ve photographed it during the day, returning at night is on my Bucket List.