What Was... (series)

What Are the Paralympic Games?
What Are the Summer Olympics?
What Are the Ten Commandments?
What Is a Presidential Election?
(with Activities, Stickers, and a Poster!)
What Is Climate Change?
What Is LEGO?
What Is NASA?
What Is Rock and Roll?
What Is the Constitution?
What Is the Declaration of Independence?
What Is the Panama Canal?
What Is the Stanley Cup?
What Is the Statue of Liberty?
What Is the Super Bowl?
What Is the Women's Rights Movement?
What Is the World Cup?
What Is the World Series?
What Was D-Day?
What Was Ellis Island?
What Was Hurricane Katrina?
What Was Pearl Harbor?
What Was Pompeii?
What Was Stonewall?
What Was the Age of the Dinosaurs?
What Was the Alamo?
What Was the Battle of Gettysburg?
What Was the Berlin Wall?
What Was the Bombing of Hiroshima?
What Was the Boston Tea Party?
What Was the First Thanksgiving?
What Was the Gold Rush?
What Was the Great Chicago Fire?
What Was the Great Depression?
What Was the Hindenburg?
What Was the Holocaust?
What Was the Ice Age?
What Was the Lewis and Clark Expedition?
What Was the March on Washington?
What Was the San Francisco Earthquake?
What Was the Titanic?
What Was the Underground Railroad?
What Was the Vietnam War?
What Was the Wild West?
What Was Woodstock?
What Were the Negro Leagues?
What Were the Roaring Twenties?
What Were the Salem Witch Trials?
What Were the Twin Towers?