Flat Design - inspired by Bauhaus

"Flat" design has been around for the past century. It was mainly inspired by the Bauhaus movement in the 1920s and evolved into the "International Typographic" or Swiss style.

Bauhaus 

In fact, Microsoft even beat Apple in the flat race with Windows 8 "Metro"

Apple recently unveiled iOS 7 to the public.

Skeuomorphism and flat design are two very different ways of representing the interactions and functions of a computer, mobile, tablet or website. Skeuomorphism seeks to replicate real-world items directly into its design. This style makes use of drop shadows, bevels, gradients and textures. Flat design rejects nearly all of these attributes, and takes on a much more minimalist approach. 

Reference

i) Element wae.(2013) 'Skeuomorphic and Flat Design trends'. Avaiable at: http://blog.elementwave.com/post/57692150765/skeuomorphic-and-flat-design-trends (Accessed: 26 June 2015)