I urge everyone to bookmark that blog; it is always a fascinating tour of the weirder and wonderfuller places on our planet. And let me leave you with this simply jaw-dropping video of undulatus asperatus in action.
(A sunscreen with a physical block like titanium dioxide or zinc oxide can be applied last, after a serum or moisturizer.) Apply a serum next and, finally, moisturizer if you need it. Polis also recommends serums or sunscreens with moisturizers built in because they save time.
Products with a thinner consistency - such as serum - should always be applied before thick face creams. Those creams with heavier consistencies can actually stop the lighter ones from penetrating the skin and doing the job they've been designed to do - practically making them redundant.