Translated from the French.

Great Wall of China : "Current day kids Annie and Nico travel back 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. Who knows, their fun fact finding journey might lead them to outer space where they can still see The Great Wall if they're lucky!"--Provided by publisher.

Great Pyramid : "Current day kids Annie and Nico travel back to--ancient Egypt. That's about 4,500 years ago, when the world's largest pyramid was built, The Great Pyramid of Giza. It's also called the Pyramid of Cheops because it was built for the Pharaoh Cheops, who wanted to be buried in it when he died. That's right--pyramids are giant tombs! It was the first of seven buildings known as The Seven Ancient Wonders of the World--and it's the only one still standing! But it still has plenty of secrets waiting to be uncovered ..."--Provided by publisher.

Hidden oil : Time travel with Annie and Nico as they witness firsthand the history and importance of oil, also known as "black gold."