Cuaderno de Sol is a sketchbook by illustrator Enrique Flores who was documented the 15-M Movement, a series of protests in Spain. He was at the Puerta del Sol square in Madrid to draw and record what he saw.

The published sketchbook is made from selected pages of his sketchbook. It seems like it's ongoing and you can follow it through the 15m tag on his blog. Text is all in Spanish though.