by Izzi Howell by Howell EXTRAORDINARY LANDMARKS TABLE OF CONTENTS Mount Rushmore......................................................................... 4 Hoover Dam ..................................................................................... 8 Statue of Liberty ...................................................................12 CN TOWER ..........................................................................................Only16 Sydney Opera House .............................................................18 London Eye................................................................................... 22 Eiffel Tower .............................................................................. 26 GLOSSARY .............................................................................. 30 READ MORE ..............................................................................Review 31 Internet Sites ...................................................................31 CriticalFor Thinking Questions ...................................31 INDEX ......................................................................................... 32 CHAPTER 1 MOUNT RUSHMORE Landmarks are famous buildings and structures around the world that many people can recognize. You might be able to picture what landmarks look like. But how much do you know about their engineering and the stories behind how, where, when, and why different landmarks were built? Only Mount Rushmore is an iconic landmark in South Dakota. The faces of four U.S. presidents are carved into the side of a mountain. Each of the carved faces on Mount Rushmore is about 60 feet (18 meters) tall. The four presidents are (from left to right) George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln. Review For 4 iconic—widely known and recognized In 1923 Doane Robinson suggested the idea Did You Know? of a giant sculpture in the Black Hills of South Dakota. Robinson was South Dakota’s state Borglum planned to historian. He thought the monument would place Jefferson to the make more people want to visit the state. left of Washington. However, the workers Sculptor Gutzon Borglum was hired to soon realized that design the faces for the monument. He chose the rock there wasn’t four presidents that were important to the good for carving. history of the United States. George Washington So they moved was the first president of the United States. Jefferson’s face to its currentOnly position to the He also helped America win its freedom from right of Washington. Great Britain during the Revolutionary War (1775–1783). Thomas Jefferson doubled the size of the United States by purchasing the Louisiana Territory from France in 1803. He was also the main author of the Declaration of Independence. Theodore Roosevelt was chosen for his work to advance the United States as a world power. Abraham Lincoln helped bring an end to slavery in the United States and led the country during theReview Civil War (1861–1865). Work on Mount Rushmore began in 1927. The U.S. government paid for most of it, but members of the public also donated money. At the time, the statue cost $1 million to build. That would be more than $15For million in today’s money. historian—a person who studies events that happened in the past Civil War—the battle between states in the North and South that led to the end of slavery in the United States donate—to give something as a gift to a charity or cause 5 Constructing the faces on Mount Rushmore was dangerous work. First, the workers had to climb 700 steps to reach the top of the mountain. Then they were lowered over the edge of the mountain on steel cables. The cables were wound up and down using a winch to move the workers. Workers used dynamite to carve about 90 percent of Mount Rushmore. They placed different amounts of dynamite to clear different sections of the granite rock. After lighting the fuse, the workers had to quickly be lifted off the mountain before the dynamite exploded. When most of the rock was gone, the workersOnly drilled holes in the mountain to weaken the rock. Then they used chisels to chip away the last bits of rock. Finally they used a drill with a special tip to smooth the surface. In total around 400 men worked on Mount Rushmore. No one was killed during construction. Workers drill holes in Mount Rushmore. This was called “honeycombing” because the holes in Review the rock looked like a honeycomb. For 6 In March 1941 Borglum died at age 73. His son Lincoln helped Carve a face finish the Mount Rushmore Workers removed 450,000 project. On October 31, 1941, tons (408,000 tonnes) of Mount Rushmore was finally rock from Mount Rushmore completed. The project had taken to create the sculpture. First, workers removed large 14 years to finish, even though the chunks of rock before using actual carving had taken only six tools to add delicate details. and a half years. This is because It would have taken them too the work slowed down during the long to carve the details from Great Depression, when the the start. Only government didn’t have enough Try carving a face from a money to pay for workers. block of air-hardening clay. By the end of 1941, about 400,000 First you’ll need to remove large chunks to create the people had visited the monument. rough shape. Then use Today Mount Rushmore is part of carving tools to add details. the National Park Service. More Ask an adult to help you use than 2 million people visit the the carving tools. monument each year. Review steelFor—a hard, strong metal made from mostly from iron and carbon winch—a lifting device in which a cable winds around a revolving drum granite—a very hard rock used in construction chisel—a tool with a flat, sharp end used to cut stone or wood Great Depression—a period of hard times from 1929 to 1939 in the United States when many people lost their jobs 7 CHAPTER 2 HOOVER DAM The Hoover Dam was built in a canyon where the Colorado River forms the border between Arizona and Nevada. In the 1920s, the U.S. government decided to build a dam to stop the Colorado River from flooding. The government also wanted the dam to generate hydroelectric power and supply water to theOnly desert region. Construction started in 1931, during the Great Depression. The Great Depression had left millions of Americans without jobs. Thousands of unemployed people found work building the dam. Review The Hoover Dam is 726 feet (221 m) tall. For hydroelectric power—electricity produced from moving water 8 unemployed—without a job Before workers could start building the Did You Know? dam, they first had to move the path of the Colorado River. This would drain the water Around 21,000 from where the dam would be built. Otherwise, men worked on the construction of the water would get in the way of construction. the Hoover Dam. They did this by building four tunnels, two through each side of the canyon. Then they put rocks into the river to block it. This forced the water into the tunnels instead. The tunnels ended after the construction site. There, the water in the tunnels flowed back into theOnly river. Colorado River Dam construction Colorado River Review This diagram shows how the path of the Colorado River was moved during the construction of the Hoover Dam. When the original path of the river was dry, the workers dugFor into the riverbed. They dug down through 130 feet (40 m) of mud and cleared it away to reach the hard rock underneath. They needed to build the dam on rock so that it would have a strong base. 9.