A new study into the science of the "selfie" photo shows how different cities take snaps of themselves. 

Researchers analyzed 656,000 Instagram pics from New York, Moscow, Berlin, Bangkok, and Sao Paulo to come to their conclusions.

In Rio they smile, while New Yorkers will tilt their head for their best angle.

The researchers found that everywhere in the world more females took selfies than men, and in Moscow there were 4.6 times more female than male selfies.

Judging by the looks on people's faces, people are happiest in Bangkok and São Paulo, and smiled the least in Moscow.