Awesome platform for those who looks forward for improving their knowledge. CIE gives you enahnced overview of where you stand at certain subjects and gie suggestion on how knowledge can be increased by setting different papers and offering solutions.
I always used to feel insecure about 'Physics'. I was scared and despite having knowledge used to make blunders when I was assessed. Then I came across with CIE not only I increase my confidence but pass my Masters in Physices with High GPA.