You are trying to install or open an app that didn't come from the Mac App Store but you got a message saying App can't be opened because it is from an unidentified developer. This is how you bypass it.
Spectacular video made of hundreds of stitched together images taken by the Mars Express spacecraft showing the Red Planet in three dimensions like never before.
Cycloramic is an app made in 2012 that can take 360 panorama shots without using your hands. It sure is a fascinating app, but what makes it even more interesting is the following story.