Good easy reads for teenage girls? and World War 1 and 2 books?

Any suggestions? I'm a 15 year old girl who LOVES books like The Last Song and Dear John (both by nicholas sparks).. do you have any suggestions for easy reads like that about young teenaged love stories (cheesy and cliche i know, but i just enjoy them). But even more than that, I love books about WWI and WWII. Ones about the nazi's and holocaust and the jews cause i just find it very interesting to read about (for example, "The Hidding Place"). I love history and reading about wars and what not, fiction or nonfiction. Thanks everybody (: