This is a 360 degree 'little planet' panorama of a medieval castle at Milaki, Evia - Greece.
Canon EOS 550D, 3/3/2012 17:56 - 17:58, Shutter Speed 1/320 x 40 shots (panorama), Aperture Value 6.3, ISO 200, Lens Canon EF15mm f/2.8 Fisheye, Focal Length 15.0 mm