Your sandbox is a place for you to experiment with
wikicode, to keep notes, to draft sections to add to articles, or for any other purpose that helps build the encyclopedia. Although your sandbox will usually be left alone by other editors, you do not have 100% control. It can't be used to host copyright violations or personal attacks on people, for example.
Have you ever added an example image to a page, only to have it removed and receive a warning? Here's a solution. If you want to test some unfamiliar wiki-markup, or practice image placement, head to the
Sandbox, where you can test to your heart's delight (or you can create your own sandbox for more demanding tests). Or open
your own sandbox by clicking on "Sandbox" on your user menu at the top of the screen.
Bonus tip: you can have as many sandboxes as you like, but only one gets displayed at the top of the page. To get to the others easily, you could list their links on your sandbox page, using it as a menu of sandboxes.
While browsing through Wikipedia, you may have clicked on Featured content from the left menu.
Featured content represents the best of Wikipedia, including articles, pictures, and other contributions that showcase excellent results of the collaborative efforts of Wikipedia. Here is the list for each of these features.