The bubble or spirit level is not among the headlining features of iOS 7, but if you are assembling a piece of Ikea furniture, hanging a picture, or otherwise find yourself in need of a level, it can save you a trip to the garage or basement for your actual level or the App Store for such a third-party app.
Apple didn't grant the humble bubble level its own app, instead choosing to hide it within another default app. Care to guess which one? Time's up! The answer (drum roll, please): the Compass app.
If you look carefully, you'll notice the new Compass app for iOS 7 includes two dots at the bottom of the screen, denoting a second page exists. And if you swipe to reveal that second page, you'll encounter the bubble level.
The level works when you hold your iPhone horizontally:
And it goes green when you are completely level:
For more on Apple's latest mobile operating system, I will refer you to CNET How To's complete guide to iOS 7.
(Via The Verge)