In 1900, American women couldn't vote. Vaccines and the radio didn't exist. It took more than a week to travel from Paris to New York. Colonial powers scrambled to conquer Africa. Only the world's wealthiest owned automobiles. By 1999, the world prepared for a computer problem that might ravage the global economy. Daily commercial flights jetted across the Atlantic. The Internet, space travel and the ability to clone animals were no longer far-fetched tales of science fiction. This year's study of the 20th century helps you understand those changes and, therefore, understand the world today.