What happens when you take the smallest value currency and put it under an extremely powerful microscope? An art exhibit from photographer Martin John Callanan explores that idea. Callanan, together with the National Physical Laboratory in England, put 166 of the world's least valuable coins under an infinite focus 3D optical microscope, resulting in nearly 4-foot by 4-foot prints. Digitally, the photos are the equivalent of 400 megapixels, and show the tiniest details of the coins, many of which are beat up from years of use.

Huge views of small change

The exhibit — which was last shown in London in September — originally aimed to highlight and preserve the low-value coins, which have already been phased out in places like Canada, Australia, and Norway. Callanan has put up versions of more than a dozen of the coins online, which can be magnified to show off all the tiny details.