Why is there almost no ancient city wall in Luoyang?

I know. London is full of smoke and chaos. Although the street lamp is on, the visibility is still poor, and you can't see anything beyond 10 meter clearly. I always feel that my eyes are blurred in front of people. But now, it is basically difficult to see its thick smoke and yellow fog over London. Hundreds of extinct birds fly back to London, and many fish return to the Thames. The dust in the air has been greatly reduced, which has made London take off the hat of "foggy city", which should be attributed to the pollution control in the past 30 years. In London, coal-fired factories will be closed or moved out of the city as far as possible, urban residents will stop burning coal, and all cars will use unleaded gasoline. It has reduced automobile exhaust emissions by more than 75% and fundamentally "driven away" pollution sources. The environmental law enacted by the British government ensures the implementation of environmental policies and specific measures. In London, littering in public places is regarded as a crime and a high fine is imposed. Smoking is strictly prohibited in public places, and offenders will be fined up to 1000. In recent years, more parks and green spaces have been established in London, so that there is no exposed soil in the urban area, and more than 10 satellite cities have been established in the suburbs, greatly reducing the congestion in the urban area. Nowadays, in London, city parks are dotted with lush trees and green grass. Basically bid farewell to the image of "Fog City" and become a clean city. However, there was smog in London last winter, indicating that pollution source remediation cannot be relaxed for a moment, and it is necessary to make unremitting efforts.

As early as the Middle Ages, the problem of soot polluting the atmosphere began to appear in London. At that time, the British Parliament also issued a decree prohibiting craftsmen from using coal during the parliamentary session. After the industrial revolution supported by coal began, because most factories were built in cities, residents burned a lot of coal to keep warm, and the smoke and dust emissions increased sharply. In the windless season, smoke and fog turn yellow and black, often hovering over the city for many days, forming the London fog described by Mr. Lao She, who once lived in London, as "black, muddy yellow, crimson, spicy and choking".

Symmetrical ancient capital-Beijing has a bird's eye view of Beijing from a helicopter. People are surprised to find that Jingshan is like a human figure with complete facial features and symmetry.

The ancient city of Beijing is a symmetrical city. It takes the Forbidden City as the center, and forms a central axis from Yongdingmen, Qianmen, Tiananmen, Wumen, Shenwumen and Jingshan to Di 'anmen, Bell Tower, Drum Tower and Andingmen. North-south parallel streets such as Dongsi and Xisi are criss-crossed by the same east-west alley, which is located on both sides of the central axis. Because of symmetry, the roads in Beijing are easy to identify. Many important buildings symbolizing the imperial power in feudal times are also neatly and symmetrically distributed around the central axis. For example, the Temple of Heaven and the Ditan where the Ming and Qing emperors sacrificed heaven and earth were built on the east side of the north and south ends of the central axis; In the east of Tiananmen Square, there is the Royal Ancestral Temple (now converted into the Working People's Cultural Palace), and in the west, there is a social altar (now converted into Zhongshan Park) for offering sacrifices to the gods and praying for the Valley. This symmetrical pattern is particularly evident in the palace buildings of the Forbidden City. Inside the Forbidden City, not only the palace buildings rise and fall, but also correspond to each other. Even the stone fences on the roadside, the turrets on the edge of the city and the sculptures on the roof are pairs, which set each other off. The neat symmetry constitutes the unique style and magnificent momentum of Beijing's urban architecture, giving people a sense of stability, breadth and majesty.

Beijing has a history of more than 4000 years. After Liao Dynasty, it was the capital of Yuan, Ming and Qing Dynasties. It represents the ancient culture of the Chinese nation and has many places of interest. Such as the Forbidden City, Jingshan, Beihai, Zhongnanhai, Summer Palace, Temple of Heaven, Ditan, Great Wall-Badaling, Mutianyu Great Wall, Zhoukoudian Chinese Ape and Neanderthal Site. Many buildings have peculiar shapes and contain rich cultural ideas. For example, the Temple of Heaven is a dome, but the altar is square, which is in line with what the ancients in China said.

Beijing is bordered by Taihang Mountain in the west, Yanshan Mountain in the back and Bohai Sea and North China Plain in the east. It belongs to temperate continental climate with four distinct seasons: dry spring, hot summer, cool autumn and cold winter. Now there are 9 counties in 10 district in Beijing, with an area of 1600 square kilometers and a population of nearly10 million. It is the political, economic and cultural center of our country. There are many tall buildings in this city. The traffic is very busy. Although the layout of modern buildings in Beijing is not as symmetrical as in the past, municipal construction still takes into account the traditional style of our country. For example, in the subway around the city, the second ring, the third ring, the fourth ring and the fifth ring centered on the Forbidden City are all symmetrical. The ancient central axis of Beijing and its extension line are being transformed into a modern central axis road, connecting Beijing-Zhengzhou Highway in the south, passing through the Asian Games Village in the north, and directly reaching Yanshan Qifeng. Among all the cities in the world, Beijing is still a unique and symmetrical city.

Paris, the flower of the world

Paris, the capital of France, is a famous historical and cultural city and one of the most prosperous metropolises in the world, and is known as the "flower of the world".

Paris is located in the north of France, in the center of the Paris Basin, across the banks of the Seine River, with an urban area of 105 square kilometers, including the city of Paris and Bali in seven surrounding provinces, with a total area of 12000 square kilometers. The population of Paris is more than 2.3 million, and the population of Greater Paris is about10.007 million. It is the largest city in France and one of the most populous metropolises in the world. Today's Paris is not only France, but also the political, economic and cultural center of Western Europe.

Paris has a history of more than 2,000 years. As the capital of France for 800 years, it is an ancient capital. At first, it was just an island in the Seine. There are only Gaul villages in the west of Paris, where they make a living by fishing, hence the name Paris. In the long historical years, small villages have been developed to the banks of the Seine River. /kloc-in the 0/2nd century, the Capé dynasty established its capital here, and since then Paris has gradually developed into a big city. Historically, Paris was the capital of French dynasties, the capital of bourgeois republics and the birthplace of French bourgeois revolution. On July 1789 and 14, the people of Paris broke through the door of the Bastille, thus starting the French bourgeois democratic revolution. Later, this day became the national day of France. 187 1 08 March 18, the working class in Paris held an armed uprising that shocked the world and established the first proletarian regime, the Paris commune. The wall of Father Lachez's cemetery in the east of Paris Commune is the place where commune members finally fought a defense war and sacrificed heroically. On May 7th every year, French working people come here to mourn the martyrs of the Paris Commune. During World War II, Paris was occupied by German fascists. Liberation on August 25th, 1945. Today, many administrative organs, party organizations and provincial administrative agencies of the French government are still located here, and some important international organizations such as UNESCO, the International Council of Women, Interpol, the International Energy Agency, the Paris Coordinating Committee, the Organization for Economic Cooperation and Development, the International Exchange and Development Program, and the International Organization for Legal Metrology are all located in Paris.

The total industrial output value accounts for about1/4 of the whole country; The number of workers in Paris accounts for about 1/5 of the whole country. The automobile industry ranks first in China, and China's largest Renault Automobile Company is located in the winding area of the Seine River in the southwest suburb of Paris. Citroen and Xinca automobile manufacturing companies are also located in Paris. The employees of these three companies account for 3/5 of the employees in the national automobile industry, and their output accounts for 2/3 of the national automobile production. The output of electrical and electronic industries accounts for 60% of the country. The output of chemical industry accounts for 30% of the whole country. In light industry, Paris has traditional clothes, cosmetics, decorations and fashionable furniture, all of which enjoy world reputation. Paris perfume is world-famous, known as the "dream industry" and regarded as a national treasure by the French. Among thousands of perfumes in the world market, Paris perfume is the most popular.

Finance, securities and insurance in Paris are very prosperous. BNP Paribas, the largest state-owned commercial bank in France, is located in Paris. There is also the French financial center, the Paris financial market, one of the important financial markets in the world, including the money market, the capital market, the foreign exchange market and the gold market. Every day, astronomical amounts of money and securities flow here.

Business in Paris is booming, accounting for about 1/3 of the national business volume. Various large-scale markets, department stores, fashion shops, restaurants, cafes and other service institutions are all over the city. Four Seasons Shopping Center, the largest shopping center in Europe, is located in La Dé fense, Paris. The famous Paris International Expo was founded in 1904, and there is a beautiful exhibition hall on the pastoral street of Elysee Palace. 1937, the modern troca Dro Exhibition Hall was completed, forming an "Expo City" that can be opened all year round. At present, dozens of professional fairs such as fashion, machine tools, food and cosmetics are held every year. In addition, Bourget International Airport also held an international air show, exhibiting more than 200 aircraft of various types, making it one of the largest aircraft markets in the world. Because the Expo lasts all the year round, it attracts more than 500,000 foreign businessmen and tourists every year, and the income is increased by more than 300 million US dollars.

Paris is the transportation hub of France, with a daily passenger flow of 6.5438+0.3 million. The land traffic of the whole country is concentrated in Paris, forming a radial traffic network. There are seven railway stations in Paris, which can lead to Belgium, Luxembourg, Italy and Switzerland, as well as Germany and Spain. Paris is also an international aviation center, with five airports that can fly to major cities in the world. Paris is also the largest inland river port in Europe, which undertakes the transportation of agricultural products, building materials, fuels and other industrial products. The deep high-speed subway running through the city from east to west is integrated with the cobweb-dense roads and railways on the ground, forming a complete transportation system.

For a long time, the French people have created splendid French culture, and Paris has become the center of French culture and education. Founded in the middle of the17th century, the French bachelor's college and four other colleges are located in Paris, and there are many academic institutions, museums and theaters in Paris. Paris has gathered 43% technicians and 60 ~ 70% researchers. There are many institutions of higher learning, such as the University of Paris, which was founded in 1253 and has a cultural influence all over the country. In Paris, various forms of cultural and artistic activities are always flourishing, and small concerts spontaneously organized by young students and citizens can be seen in many squares of the city.

Paris has a glorious revolutionary tradition, leaving many glorious footprints of proletarian revolutionaries. Marx and Lenin once lived in Paris. Many older revolutionaries in China went to Paris in the 1920s to study part-time and explore the revolutionary truth. There is a three-story building in Godfrey Street near Piazza Italia in the south of Paris. Zhou Enlai lived here in the 1920s. 1979 10, in memory of Zhou Enlai, the French government hung a marble memorial spleen in his former residence. A bronze statue of Zhou Enlai is embedded above the commemorative card, and six lines of gold are engraved below the bronze statue. All China people who come to Paris are eager to see Zhou Enlai's former residence with their own eyes.

There are 6,500 streets in Paris, with a total length of over 1300 km, of which the most charming street is the Elysee Pastoral Street. The street runs through the city center and is connected with Star Square. 12 Boulevard radiates from the square and connects with thousands of streets and alleys in Paris. In the center of the square stands the Arc de Triomphe, 48.8 meters high, 45.5 meters long and 22 meters wide. The wall is carved with photos of famous historical figures, among which the group sculpture of La Marseillaise is the biggest scene. The arch is engraved with the names of 386 generals who fought alongside Napoleon. Under the arch is the tomb of the unknown soldier, and the ever-burning lamp never goes out all year round.

La Dé fense is a collection of buildings of various shapes and colors. Experts believe that it is a monument in the history of urban architecture and an "open-air museum" of modern advanced buildings. Eight 30-story skyscrapers and 20 40-story skyscrapers are all made of glass, and they always shine and shine in the sun or at night. This office building named "Ark" is shaped like a Chinese character "Hui", with rooms on both sides and upper parts, and the middle is empty, so it is called the new "Arc de Triomphe".

La Defense Satellite City occupies a certain position in the economic activities of France and even the world. The 2 million square meters office building in Satellite City is leased to more than 600 companies from all walks of life, and more than 654.38 million employees work here. 10 of the top 20 French enterprises and10 of the top 100 enterprises in the world all have offices here.

The eastern part of the right bank of the Seine River is a residential area for employees. To the west is the most prosperous commercial and senior residential area in Paris, with beautiful environment and wide streets. Many big banks, companies, exchanges and supermarkets are located here.

The Latin quarter on the left bank of the Seine is a famous cultural district, where there are cultural and scientific institutions such as the University of Paris and the National Library built in the Middle Ages, as well as newly-built institutions of higher learning in recent years. Mamont District, located in the north of the city, is a residential area for ordinary citizens and workers. The streets here are narrow and the houses are mostly old buildings.

The Eiffel Tower, the symbol of Paris, stands as high as an iron giant on the banks of the Seine River in the center of Paris. This tower was built to celebrate the 0/00th anniversary of the French Revolution/KLOC-and was named after its designer gustave eiffel. The Eiffel Tower is inextricably linked with Paris. It is the symbol of Paris and the pride of the French people. The downtown area around the iron tower is an administrative area, where French state institutions, UNESCO and foreign embassies are all located, and the places of interest are also very dense.

The Elysee Palace is located on the spacious Elysee Palace Garden Avenue in front of the Arc de Triomphe and has always been the seat of the presidential palace of France and China. It's just northeast of this street roundabout, across the street from the Grand Palace (the art exhibition hall in Paris). The Elysee Palace was built in1early 8th century and completed in17 18. Originally, it was a venue for dancing, and then several large-scale expositions were held. It was also used as a palace when foreign heads of state visited France. As the French Presidential Palace from 1873, it has experienced 20 presidents so far.

The Louvre is an art treasure house, which concentrates the essence of world culture and art. It is located on the right bank of the Seine River and was built in 1 190. Originally the castle of Prince Philip, it was converted into a palace by Charles V in the18th century. 1793 During the French Revolution, it was officially changed to the National Museum of Art. So far, the Louvre has collected more than 200,000 paintings, sculptures and other works of art, and is famous for its rich collection of classical paintings and sculptures. Originally a large palace complex, the Louvre is one of the most precious buildings in the French Renaissance.

When Notre Dame de Paris is mentioned, many people can't help thinking of Hugo's novel of the same name. /kloc-at the beginning of the 0/9th century, the publication of Hugo's novels aroused people's interest and immediately decided to rebuild Notre Dame, which had declined at that time.