You Wouldn't Want to Be an Aztec Sacrifice by Fiona Macdonald illustrated by David Antram*

Created and designed by David Salariya
Gruesome Things You'd Rather Not Know
My boys love this series!
Although gruesome, the reader learns a lot of other interesting facts about the Aztecs. 
When given a stack of books to read about the Mayas, Aztecs and Incas, they both choose to read this one!
*Highly recommend (but not for sensitive readers).
-Borrowed from the library.