Emperor Zhu Yuangzhang, the founder of the Ming dynasty, was of a very Chinese disposition: He loved walls, the longer the better.
What is it about Chinese emperors and fortification? They were constructing walls along their borders from as early as the 7th century BC! So, soon after he captured Nanjing in 1356 and declared it his capital, Emperor Zhu, in true Chinese tradition, ordered the construction of the longest city wall. The result was an outstanding achievement of architecture, science, technology and military art.

Over 200,000 labourers toiled at it for 20 long years, digging up seven million cubic metres of earth to create this massive battlement that stretches for 33km and stands 20m high. Given that Zhu spent 30 years at war with various warlords to liberate China from the Mongols, his affection for fortification was not merely fanciful: the wall is masterpiece of military defence.

Stories surrounding the wall are as interesting as the wall itself. There's one behind how the Zhonghua Gate got its name. Zhonghua or the Gate of Gathering Treasure is the strongest among the 13 gates in the ancient wall. Legend has it that during construction, the city wall kept collapsing. Emperor Zhu was advised to borrow a treasure bowl from the Shen clan in Suzhou and bury it at the foot of the wall to prevent any more collapses.

Zhu did more that that. He seized the bowl by force and buried it. Later the Zhonghua Gate was built and is the only part of the wall that is still well preserved. Within the gate there are 27 caves which were used to store military supplies. The enormous fortress, covering more than 15,000 square metres, had several rooms inside, each of which could fit in a thousand soldiers. At the top of the outer wall there were 13,616 battlements for city defenders to observe the enemy or dodge arrows.

And to think that glutinous rice went into the construction of this fortress! Into the brickwork joints was pored a mixture of lime, tong oil and water in which rice had been cooked. This coagulated mixture was very strong, which is why the city wall has stood for such a long time. Battle-scarred from the war of the Taiping Heavenly Kingdom and the 1911 Revolution, this 14th century city wall was listed as an important cultural relic under state protection in 1988.

Today, nearly 21 km of the wall still stands - more than 20 m high at some points - and is dramatic focal point throughout much of Nanjing city. Nanjing, the capital of Jiangsu Province, lies on the southern bank of the Yangtze, and at the foot of the Purple and Gold mountain.

The Nanjing city wall is quite different from ancient city walls in Beijing and Xi'an, which were constructed in the traditional style with square of rectangular structures. Instead, this one is built in a winding free style suited to the city's complicated topography.

The best maintained section of the wall surrounds Xuanwu Lake Park. The lake, which was once used for naval exercises during the Song dynasty, has five tiny islands, connected by bridges, with elegant teahouses, restaurants, gardens, pavilions, an open-air theatre and even a zoo.

Although the main entrance to the park is on Zhongyang Lu, a favourite spot with the locals is the Jiefang Men (Liberation Gate) as it is less touristy. Inside, you'll find old men fishing and people picnicking, paddle-boating or riding tandem bicycles.

Enter through Jiefang Men, turn right and you will find a staircase that leads you through a hole in the city wall. It takes you trough a bizarre dormitory-like office built inside the wall and eventually up and back out again.

The top of the wall makes for a comfortable, even exhilarating walk, about half an hour in either direction on a wide, solid path that was rebuilt in the 1980s. And the view is expansive - the shimmering lake to the north and the Purple Mountain to the east where Zhu's tomb still stands, keeping a watchful eye on the wall that is his lasting legacy to the city of Nanjing. (*SilverKris)