Bosch's Garden of Earthly Delights needs to be observed in detail. Wikipedia has an excellent, high-resolution image of it with magnifications for each detail of the work:
http://en.wikipedia.org/wiki/File:The_Garden_of_Earthly_Delights_by_Bosch_High_Resolution.jpg
Bruegel's Netherlandish Proverbs is one of several paintings Bruegel did that are really early forms of detail-hunting pictorial games (like Where's Waldo). Depicted above here are a series of proverbs -- you can read a list of the proverbs and what they mean at this website: http://en.wikipedia.org/wiki/Netherlandish_Proverbs.
http://en.wikipedia.org/wiki/File:The_Garden_of_Earthly_Delights_by_Bosch_High_Resolution.jpg
Bruegel's Netherlandish Proverbs is one of several paintings Bruegel did that are really early forms of detail-hunting pictorial games (like Where's Waldo). Depicted above here are a series of proverbs -- you can read a list of the proverbs and what they mean at this website: http://en.wikipedia.org/wiki/Netherlandish_Proverbs.