Sia!

I'm pretty sure most of you here know who Sia is. If you don't, she's the one who sings Titanium, Cheap Thrills, Chandelier, and many other songs. She has also written songs for Brittany Spears (Perfume), Rihanna (Diamonds), and a few other singers.

She is also well known because she seems to be the only famous singer who hides her face. 

What do you think about her? If you like her, what's your favorite song by her? If you don't like her, explain why below! :)