Mexico City - geography.

Mexico City - geography. I INTRODUCTION Mexico City, capital of Mexico and the center of the nation's political, cultural, and economic life. Its population of 18.7 million (2003 estimate) makes Mexico City one of the largest metropolitan areas in the world. It is also the seat of Mexico's powerful, centralized federal government. Much of the political decision-making for the nation takes place in Mexico City. Culturally, Mexico City dominates the nation since most of Mexico's leading universities, intellectual magazines, newspapers, museums, theaters, performing arts centers, and publishing firms are located in the capital. Mexico City is built on the ruins of Tenochtitlán, which was the capital of the Aztec Empire. The Aztec developed an advanced civilization and dominated most of Mexico during the 15th and early 16th centuries. In the early 16th century Spanish explorers landed in Mexico and conquered the Aztec. The Spaniards founded Mexico City on the ruins of the Aztec capital, and it soon became the leading urban center in Spain's American colonies. Mexico won its independence in the 1820s, and Mexico City became the capital of the new nation. Mexico City expanded at a phenomenal rate in the 20th century. The metropolitan area absorbed surrounding communities and rural areas to become a sprawling, modern urban center with a thriving economy. The city's rapid growth resulted in major urban problems, including poor housing, pollution, inadequate sanitation, and uncertain water supplies. Mexico City falls within the jurisdiction of the Federal District (in Spanish, Distrito Federal), which is the seat of Mexico's federal government. The Federal District functions as the state and city government for Mexico City and the other communities within its jurisdiction. The Federal District borders the states of Mexico on the north and Morelos on the south. Mexico City is located in the south central portion of the country. It lies at the southern edge of the Mexican central plateau in the Valley of Mexico, a basin at an altitude averaging 2,300 m (7,500 ft). The Valley of Mexico is ringed by a series of mountain ranges. On the eastern edge of the basin are the permanently snow-capped twin volcanoes, Iztaccíhuatl (5,286 m/17,343 ft) and Popocatépetl (5,452 m/17,887 ft). To the west, the mountains separate the Valley of Mexico from the Valley of Toluca and the Lerma River basin, the present source of much of the city's water. The surrounding mountains can trap air pollution within the valley, particularly when there is a thermal inversion (warmer air passing over the valley and trapping cooler ground air beneath it). Mexico City's climate is fairly consistent and steady, a product of both the city's latitude, which is south of the Tropic of Cancer, and its elevation of 2,239 m (7,347 ft). Although the city is located in a tropical climatic zone, the city's extremely high elevation produces a moderate climate with a narrow range of temperatures. The average annual temperature is 16°C (61°F). The coolest season runs from November to February; the coolest month is January, with average temperatures ranging from a high of 21°C (70°F) to a low of 7°C (44°F). The warmest period is from April to June; the average temperatures in May range from a high of 26°C (78°F) to a low of 12°C (54°F). Mexico City has a distinct rainy season from June through October, during which four-fifths of its annual 850 mm (33 in) of rainfall occurs. II MEXICO CITY AND ITS METROPOLITAN AREA Mexico City covers an area of 1,480 sq km (571 sq mi). It is the central, urban core of the Federal District, which was created around the capital city by the 1824 constitution. The Federal District occupies an area of 1,547 sq km (597 sq mi). However, the larger metropolitan area of the capital extends well into the neighboring states of Mexico and Morelos. The metropolitan area largely fills the basin floor of the Valley of Mexico. Its urban development has engulfed a number of old, once-independent towns, such as Coyoacán, creating surprising pockets of colonial architecture in the midst of 21st-century suburban sprawl. Growth has extended to the western edge of the basin and is beginning to creep up the foothills on its western face. To the south the city has reached the town of Tlalpan on the edge of the valley. To the east, poorer areas stretch for miles in a string of ciudades perdidas (Spanish for "lost cities"). A classic example of the city's unchecked expansion is the sprawling neighboring community of Netzahualcóyotl, in the state of Mexico. Economically and socially an integral part of Mexico City, the settlement was a sparsely populated lake bed in 1960. Its population grew to a little more than 500,000 people in 1970 and then more than doubled to 1,101,619 in 2008, making it one of the largest cities in the country. It had to deal with problems characteristic of much of the greater metropolitan area. In the late 1990s only 10 percent of the streets in Netzahualcóyotl were paved, and few public services were available. The people faced poverty, massive unemployment, malnutrition, and soaring infant mortality rates. Since Aztec times the Zócalo, known officially as the Plaza of the Constitution, has been the hub of Mexico City. During the Aztec Empire, this public square was the point where three great causeways converged to connect the city, which was an island in Lake Texcoco, to the mainland empire. Archaeological excavations have exposed the lower levels of the Aztec pyramids and temples in both the Templo Mayor, just behind the Zócalo, and the Plaza of the Three Cultures, a short distance to the north. The excavations are important not only as archaeological sites but also as symbols of Mexico's rich past. When the Spaniards conquered the Aztec in 1521, the Spaniards destroyed a great Aztec palace and temple at the site. They replaced them with a church and palace. The small, original Spanish church on the north side of the plaza was replaced by the Metropolitan Cathedral, which was built between 1573 and 1813. On the plaza's eastern side is the National Palace, the present seat of the Mexican government. Spanish colonial authorities began building the palace in the late 17th century to replace the residence of the Spanish viceroy (colonial governor), erected by conqueror Hernán Cortés and destroyed by rioters in 1692. Work on the palace continued intermittently throughout the 1900s, and the entrance is now adorned with murals by 20th-century Mexican painter Diego Rivera. A rather austere and daunting public space, the Zócalo is the scene of major public ceremonies and military displays. The Zócalo continues to be filled with significance for many Mexicans. It is a sacred place for Native Americans seeking to identify with their precolonial past. It is also a rallying point for political protesters and the location for massive Independence Day celebrations each year on September 16. Slightly to the west of the Zócalo, in the heart of the city's commercial and shopping district, is the Alameda, a park of tree-lined walks laid out in 1592. The park is bordered on the east by the imposing 19th-century Palace of Fine Arts, with its theater and murals. Also nearby is the 44-story Latin American Tower, downtown Mexico City's tallest structure, which houses professional and commercial offices. Farther to the west is the Paseo de la Reforma, an elegant, tree-lined boulevard that is 60 m (200 ft) wide. Seven landscaped traffic circles, or glorietas, line the Paseo de la Reforma and are marked by monuments honoring Mexico's past. These monuments include landmarks such as the statues of Mexican president Benito Juárez and the "Angel of the Independence," a symbol of Mexico's national identity. The Paseo de la Reforma passes some of Mexico City's finest shops, embassies, and offices on its southwesterly course to the 400-hectare (1,000-acre) Chapultepec Park. Stands of trees fill the park, which has extensive recreational facilities, including a lake, fountains, museums, a zoo, and an astronomical observatory. In precolonial times Aztec emperors used Chapultepec as a retreat. Today it offers some indication of the former natural beauty of the valley. The park houses some of Mexico's most important public buildings, including Chapultepec Castle. Construction of the castle began in 1783. Positioned on the park's highest elevation, the castle functioned as a fortress during colonial times. It once served as the presidential residence and now houses the National Museum of History, which includes murals by 20th-century Mexican painter Juan O'Gorman. Los Pinos, the official residence and working offices of the president, is also on the grounds, but it is not open to the public. Chapultepec Park also contains several museums. The most important is the National Museum of Anthropology. Other museums include Mexico's Museum of Modern Art and the Museum of Na...