The Great Wall of China is among the best-known landmarks in China and a top tourist attraction. Yet it has been mentioned lately by both Foreign Minister Wang Yi and US Republican presidential candidate Donald Trump for two very different reasons.

In his talk at the Center for Strategic and International Studies on Feb 25, Wang tried to reassure the American audience why China will not replace the US.

"The reason is simple, because we're not the US," he said, triggering laughter from people such as former US ambassador to China Stapleton Roy, who understands Chinese well.

Wang went on to say that China will not become another US. "In the blood and the veins of China, there is no vein of expansionism," he said. "There is no mentality or urge to be saviors of the world."

He cited the Great Wall built more than 2,000 years as an example of Chinese non-aggressiveness, saying, "We built the Great Wall of China for self-defense."

"That is the special characteristic and the very typical expression of the features of the Chinese culture. And such a feature, ingrained in the blood or the genes of China, will continue," said China's top diplomat.

To many well-versed in Chinese culture, that also explains the rationale behind many of China's actions that are non-aggressive and defensive in nature, whether it's anti-access/area denial capability or the minimum nuclear deterrence capability.

It's in sharp contrast to the US, which has a military budget larger than the next eight countries combined and maintains by far the largest nuclear arsenal, one that could destroy the planet multiple times over.

In an article in The Nation last December, David Vine of American University quoted the Pentagon as saying that the US has around 800 military bases in foreign countries, including 174 in Germany, 113 in Japan and 83 in South Korea.

"Although few Americans realize it, the United States likely has more bases in foreign lands than any other people, nation or empire in history," Vine said.

Wang's speech, however important in helping people understand China's foreign policy, was not well covered by the US news media.

But Americans have been hearing repeatedly about "Great Wall" ever since last summer whenever Trump shouts about the wall he will build on the US' southern border to stop illegal immigrants coming from Mexico.

"I will build a great wall. No one builds a wall better than me. Believe me. I will build very inexpensively. I will build a great wall on our southern border, and I will have Mexico pay for that wall. Mark my words," he said in a rally in New York in June 2015. He even touted that the wall had to be beautiful because it would probably be called "The Trump Wall".

Though such words from Trump have won praise from his supporters, they have also triggered widespread anger both inside and outside the US. Former Mexican president Vicente Fox lashed out at Trump, comparing him to Adolf Hitler. During a trip in Mexico City 10 days ago, US Vice-President Joe Biden said he felt "almost obliged to apologize" for Trump's remarks about Mexico.

Trump has claimed that "I already know what it should look like." Ironically, some US publishers, such as the National Geographic, have tried to figure out what it would look like to build a roughly 2,000-mile-long wall along the border between the US and Mexico.

Others have tried to figure out how much cement would be needed, as Trump at one point said the wall would be 55-feet tall, another time 35-to-40 feet, and then 45 feet.

Some engineers have said that using concrete would not work because it would just bake and crumble under the hot southern sun. The most feasible plan had to be precast planks as seen along highways, something Trump has also talked about.

While Trump noted the wall would cost $8 billion, others estimate the price tag would be much higher.

In his Super Tuesday speech in Florida on March 1, Trump said building the wall would be easy, like "peanuts", because the Great Wall of China was built 2,000 years ago and was 13,171 miles long.

"They (Chinese) didn't have… tractors, they didn't have cranes, they didn't have excavation equipment," he said.

China's Great Wall is the longest wall ever built in human history. Some have described it by saying that it would reach outer space if turned end-on-end, because the Global Positioning System (GPS) satellites are in an orbit only 12,540 miles high.

Whatever Trump's intention, his plan for a great wall has been perceived by the Chinese largely as a joke by a comedian-type politician.

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