The Mandelbulb, the 3D version of the mandelbrot set.
It was discovered at the end of 2009 by Daniel White & co in this thread at fractalforums: http://www.fractalforums.com/3d-fractal-generation/true-3d-mandlebrot-type-fractal/
This 3D print of it has three interesting aspects, first: you can see all the famous areas, like "the spine", "the cave of lost secrets" (as Daniel named it ;) ) and the "tower" and the mini-mini bulbs.
Second you can see the INSIDE as it really looks, even the small holes which leads into the minibulbs.
And third, you can WEAR it! :)
In the image you can see my wife wearing it, sadly it is a little too small for my own hand, but it is possible to carefully saw through it at the thinnest part in the bottom to make it open up a more.
Sorry it is a bit expensive, but it takes a lot of material to make it big enough, and it is very rigid, not like my first Bracelet:
…much cheaper, but has a prototype feeling, the Mandelbulb Bracelet is a real jewel.
Mandelbulb 3D > Fiji > Meshlab > Netfabb > Shapeways