The area around the canal was very

The area around the canal was very dangerous. It had a tropical climate. That means it was very hot and wet, with about 150 inches (267 centimeters) of rain a year. The heavy rain often flooded the rivers. There were mosquitoes. No one knew that mosquitoes caused malaria. Thousands of workers died from malaria and accidents.
One of the greatest engineering achievements of the twentieth century was the Alaska Pipeline. In 1968, an oil company found the largest oil field in North America. How could they get oil from Alaska to the rest of the United States ? They worked with other oil companies to build a pipeline.
The Alaska Pipeline is the longest pipeline in the world. It carries oil for 800 miles (1287 km) through the cold, hard Alaskan wilderness. It crosses three mountain ranges and more than 800 rivers and streams. More than 70000 workers built it. They worked for nine years in sub-zero temperatures. They completed the work in 1977. Since then, over 15 billion barrels of oil have traveled through the pipeline.
There are many other amazing engineering projects around the world. For example, the Great Wall of China was the largest building project in history. The Great Wall is approximately 4500 miles (7242 km) long. Another exanple is the Pan-American Highway. It is about 20300 miles (32670 km), and it is the longest road in the world. It goes through Canada, the United States, Mexico, Central America, and South America. Can you think of other examples of great engineering projects ? Which project do you think is the greatest of all ?