This visually exciting and reader-friendly coverage of important events and trends that shaped the 20th century uses memorable and surprising photographs, chronologies, time lines, fact boxes on trends and trivia, and authoritative text from noted historians, scientists, and explorers to bring to life this remarkable century. Organized conveniently by decade, each section begins with an essay by an eminent historian that addresses the prevailing topic or issue of the decade. This is followed by twenty pages of yearly chronologies for each decade. These spreads are lively and self-contained, with handy reference features that make any year easy to find and understand. They cover events of serious national or worldwide importance as well as factors that affected the daily lives of millions of Americans. Between each decade are special thematic essays describing the National Geographic's long-standing contributions in the areas or archaeology, exploration, animal studies, photography, cartography, the environment, Earth's forces, underwater exploration, and space. Sprinkled throughout are spreads that highlight National Geographic magazine's own coverage of significant events of each decade.Includes bibliographical references and index