a hat!

In the past, hats were an indicator of social status, but now it's more like a fashion accessory. One of the best features of a hat is that it can be adapted to any outfit in any season. 
Even tough hat has been historically considered a man's hat, now its for both sexes for fashion and for function. Throughout history hats identified social standing and removing a hat was a gesture of respect. In the 'old days', men took off their hats in Christian churches, when they entered someone's home, when greeting a boss, and always in the presence of a lady. Ladies were entirely exempt from 'hat rules', wearing them whenever and where every they wished. While some of these customs are now historical footnotes, even in today's casual culture men and women still remove their hats as a sign of respect. 
In fashion terms, hats are a very noticeable accessory because the onlooker's attention is first drawn to the face. A hat is the most noticeable fashion item anyone can wear. The old saying goes 'if you want to get ahead and get noticed, then get a hat'. Indeed the word 'ahead' means just that one head further forward. 
Stylish and mysterious look that can be as casual or formal as you feel. 

Photos from : Gary Pepper Vinage; Sincerely, Jules; Google Search Images; Modie Junkie; Stokholm street Style; Amlul.com; Fashion Me Now; Style.com; Rumi Hanna; le 21; Candice Lake;