The largest structure ever built was not made by humans, but by incredibly tiny organisms known as coral polyps. Over the course of tens of thousands of years, these small organisms have put together a collection of nearly 3,000 reefs, known as the Great Barrier Reef, which form a collective stretching across 130,000 square miles. Scientists have counted about 1,500 different fish species that use the reef, and it's estimated that 1.5 million birds use the site.
Addison is like a lot of other girls her age. Her interests include celebrities, fashion, and blogging. She loves spending time with her friends at the mall. And her personality is both bubbly and infectious. Not as infectious, however, as Hepfolk. After the deadly Hepfolk virus turned over 80% of the world into zombies, Addison started learning quickly that life was nothing like it used to be. Surviving after the zombie apocalypse can be hard for anyone, including teenage girls like Addison.