Children learn to ride them early in life. Weekend warriors use them for exercise. People even ride them to and from work. The bicycle is a source of entertainment, but it is also an invaluable means of transportation. Today, there are about two times more bicycles than cars worldwide. This fun and engaging resource discusses the development of the bicycle, its use throughout its two-hundred-year history, bicycle use around the globe, and modern innovations....

Young readers are fascinated by how the things around them are constructed. This volume will answer many of the questions they have, by first addressing the job of civil engineers and then explaining how some of the world's greatest engineering marvels were built. Students will learn how tunnels such as the English Channel Tunnel are built under water; how dams like the Hoover Dam are built and the purpose they serve a community; and why the Panama...

Anthropologists, scientists who study humans and their ways of life, are continually finding and interpreting artifacts left by our earliest ancestors. They have helped us understand our origins as well as the intriguing cultures that developed as humans spread across Earth. This volume is a concise introduction to this diverse and fascinating field. Readers will learn of the various branches of anthropology, including archaeology and biological anthropology,...

Given the vastness of the universe, it is not difficult to imagine the possibility of life-even intelligent life-beyond Earth. Yet whether any extraterrestrial beings have ever made contact with us and if any evidence of this contact exists, remains widely debated. Evaluating tales of alien encounters and UFO sightings with a critical eye, this absorbing volume considers the possibility of extraterrestrial life by carefully separating scientific fact...

Even as the national bird of the United States, the bald eagle has not always been universally beloved. Hunting, poisoning by DDT, and other human activity reduced bald eagle numbers from many thousands to fewer than 1,000 by the 1960s. Young readers are introduced to this incredible bird and the story of its recovery after it reached the brink of extinction. They will learn what actions were undertaken to protect the species and how its disappearance...