Jigsaw Puzzles - Parks of the World is an amazing collection of puzzles that offers multiple pictures of natural parks from all over the world. The parks are divided into categories, including civilization, peaks, fauna, flora and water. The trial version will only allow you to play the first puzzle from each category, but that's enough to see what the game has to offer.
All the puzzles feature different difficulty levels to choose from, which are determined by the number of pieces you need to put together. The range of pieces varies from one puzzle to the other. Once you start a puzzle, the clock will start running, and the faster you complete a puzzle, the more score you will get. You will be able to mix the pieces, preview the entire image for guidance, show the edges for extra help, rotate the pieces, move groups of pieces, change the background color and view the solution. What is more, all puzzles can be saved at any stage to continue them later.
In short, if you are a real fan of puzzles, I recommend you try Jigsaw Puzzles - Parks of the World.