1. The Roof of the World — Transcendent Tibet
From space or for an explorer the Qinghai-Tibet Plateau and its surrounding mountain ranges, known as the Roof of the World, must be the most impressive thing about China. Remote, pristine, and transcendent, this is the destination of dreams.
The Roof of the World has a ll the world's highest 100+ peaks, including Everest and everything over 7,000 meters, and many other highest things, e.g. the highest railway and temple (Rongbuk), and the largest, deepest canyon — Yarlung Tsangpo. It is the largest highland plateau, remotest place outside the polar regions, and source of more big rivers than anywhere else (Yangtze, Yellow, Tsangpo-Brahmaputra, Ganges, Mekong, Salween, Indus, …).
(The Roof of the World, though technically a multi-country wonder, with e.g. Mount Everest actually being in Nepal, is included as a Chinese wonder as no other country has such a great claim on it.)
2. Chinese — The World's Most Complex and Largest Language
The Chinese language (Mandarin) has the most native users in the world today (1.3+ billion), and worldwide interest in learning it is growing.
The Chinese written language, i.e. Chinese characters, is one of the oldest (about 4,000 years old), and the only pictographic/ideographic language in modern use, with 100,000+ characters, but only 3–4,000 required for functional literacy.
Characters (汉字hanzi) convey meaning often through symbolic units, quite unlike phonetic written languages. Profound and elegant, they lend themselves to beautiful calligraphy and poetic phrase and idiom.
3. The Unification of China — "Qin-a" — by Emperor Qin
Who could not be enchanted by First Emperor Qin's vision of "peace through unity of a nation", as portrayed in the film Hero. Qin's vision paved the way for what is now the largest nation in the world.
First Emperor Qin's empire (221–206 BC) was short-lived, but his accomplishments were great, and his impact long-lasting. Han, longest ruling dynasty (206 BC – 220 AD) and namesake of the Chinese (majority) people, 汉族 Hanzu, and language, 汉语 Hanyu, i.e. Mandarin, wouldn't have ruled over a unified China if it weren't for Qin (pronounced "chin"), whose namesake is China, and neither would subsequent dynasties and governments.
The Greek, Roman, Muslim, Mongol, and British Empires were all bigger than Qin's, but none of them now remain bigger than China, now or then. The pyramids are bigger than Qin's tomb, and so is the Taj Mahal, but no mausoleum has anything as remarkable in detail and meaning as the Terracotta Army, representing Qin's army, who conquered to unite.
4. The Great Wall of China — the Original Wonder Wall
Nothing remotely like the Great Wall of China exists. It is the greatest human construction project ever, in terms of man hours and lives expended, and it is by far the world's longest wall.
The Qin-Han Great Wall (another part of Emperor Qin's vision) ran 5,000 km from North Korea almost to Xinjiang. The linking of the walls of the Zhao, Yan, and Qin states resulted in a longer and more northerly Great Wall than the current Ming Wall.
5. The Yangtze Dams — a Massive Harnessing of Nature
The Yangtze Hydroelectric and Flood Control Project eclipses all comparable engineering feats. Once an annual cause of flooding, destruction, and loss of life, the taming of the Yangtze has turned a dangerous river into a major transport artery, electricity producer, and source of tourist revenue.
Envisioned by Sun Yat-sen in 1919, the Gezhou Dam wasn't completed until 1988, stabilizing the Yangtze for the construction of the Three Gorges Dam upstream (virtually complete in 2012). The world's largest hydroelectric plant produces 10% of China's electricity! The two dams allow massive cargo ships 2,400 km (1,500 miles) inland, all the way to Chongqing.
6. China's Last 35 Years of Development — Simply Awesome
In 1978 Deng Xiaoping's economic reforms awoke the "Sleeping Giant", and China's phenomenal economic growth (sustained at around 10% for 30 years) is only just seeing signs of slowing down.
During the last 35 years China's construction has increased to the point of using nearly half the world's steel and concrete output; an unprecedented 350+ million people have become urbanized, and even more have been liberated from poverty. China's development into the "factory of the world" has captured the largest slice of the global supply chain. See more on Developing China.
7. Chinese Culture— Last, But by No Means Least
This final wonder is a broad category covering the huge cultural contribution China has brought to the world: Chinese tea, Chinese food, architecture and landscaping, fengshui, Daoism, TCM, festivals and customs, kung fu, tai chi, Chinese opera, Chinese music, …