Ring Nebula (Messier 57)

From Earth’s perspective, the nebula looks like a simple elliptical shape with a shaggy boundary. However, new observations combining existing ground-based data with new NASA/ESA Hubble Space Telescope data show that the nebula is shaped like a distorted doughnut. This doughnut has a rugby-ball-shaped region of lower-density material slotted into in its central “gap”, stretching towards and away from us.

Image Credit: NASA, ESA, and C. Robert O’Dell (Vanderbilt University).
Explanation from: http://www.spacetelescope.org/images/heic1310a/