If you're not dark skinned*, but living in the subtropics or tropics, please for the love of all, wear a hat.
A proper hat, not a ridiculous baseball cap.
(Also, you're probably on someone else's country. Show some respect.)
(* if you're dark skinned, firstly, on behalf of my ancestors sorry for all the bad things my peeps have done to your peeps. Also situation is more complicated. You'll need a bit of sun for vitamin D, but don't go nuts m'kay?)