Look at these for size comparisons –
‘A Sense of Scale’
Some of his stuff at the very top is plain old wrong - the diameters of a proton and a neutron are 1.2 x 10^-15 meters and there is no such thing as a diameter of an electron. But he lists his sources for it however misguided they or he are. But he has everything from the smallest to the largest in there with references. (but no elephants!!) 
Above is official NIST data for anyone that knows how to interpret it. It is not nearly as interesting but is a world standard for measurements. I used to live about 6 miles from them.
Mike Dubbeld