The feet of a jumping spider are covered with lots and lots of hairs, organized as numerous larger hairs each tipped with a tuft of much finer hairs called "setules". The setules are attracted to solid surfaces by very short-range van der Waals forces that can be broken and re-established an indefinite number of times without weakening. Individually, the attractive forces are tiny, but summed over the huge number of them, the aggregate force can be 170 times the weight of the spider! At least, that's what these articles say: "Spiders make best ever Post-it notes" and "Spiders get a grip".
An optical image like I've posted here doesn't have enough resolution to show the individual setules, but I believe the tufts of them can be seen as fuzzy gray blobs at the ends of the black hairs.
Another interesting feature visible in this image is some "beading" visible on many of the long sensory hairs. At first I thought this might be an artifact of the stacking procedure. But the beading is present even in individual frames, so I think it's real. What is its significance, I have no idea.
It's the usual situation -- get close, get questions. Extreme close-ups are seldom boring!
--Rik
Canon 300D, 10X NA 0.25 achromat on 180mm extension, stacked by Helicon Focus at 0.00025 inch. Cropped to about one half frame width, shown here at about 200X.
The web page linked above references an article published 19 April 2004 in the Institute of Physics journal Smart Materials and Structures).
More info and additional pictures can be found by visiting http://www.iop.org/ and searching for "setules".
I think Gecko lizards uses van der Waals forces too. 
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