Mimi, Papa, Grant and Christina visit their pen pals in China and find themselves caught up in a mystery.

Thousands of miles from home, Grant Christina, Mimi, and Papa look out the window of their airplane at the winding-snake wall _ endless as far as they can see.

Grant, Christina, Mimi, and Papa explore China in a search for treasure, after Grant finds a mysterious map in the seat pocket of the airplane.

"Discover the fascinating mysteries surrounding the Great Wall of China. An iconic symbol, the wall's sections, trenches, and barriers stretch across more than

A “gripping, colorful” history of China’s Great Wall that explores the conquests and cataclysms of the empire from 1000 BC to the present day (Publishers