Engage your most struggling readers in grades 3-6 with Red Rhino Nonfiction! This new series features high-interest topics in every content area. Visually appealing full-color photographs and illustrations, fun facts, and short chapters keep emerging readers focused. Written at a 1.5-1.9 readability level, these books include pre-reading comprehension questions and a 20-word glossary for comprehension support. There is a United States Air Force base in the Nevada desert once so secret it never appeared on maps and was rumored to house alien spaceships.