Present day kids Annie and Nico travel back in time to ancient China to witness the construction of one of the most impressive architectural feats: The Great Wall of China. A system of walls and borders built to bolster the Silk Road and keep out intruders. Discover all the ins and outs of this gargantuan structure (in fact: it's comprised of 16 walls) with Nico and Annie as your friendly time-traveling tour guides.