The Meduza II was a Polish-designed underwater habitat constructed in 1968. Polish builder Karwik has miniaturized the submersible in LEGO form, and the resulting MOC and presentation is awesome.
Something was triggered in my brain's "happy center" when I realized that everything in the above photo - including the ropes and tubes - is made out of LEGO. The photography is stunning as well, really making it seem as if the picture was taken in the murky depths of the Baltic Sea.
Check out this Flickr album to see some more angles.