what do you understand about the formula E=MC^2

well friends, i have heard and studied many thing about the world famous formula E=MC^2. some are trying to prove it wrong. what is the fact? can anyone tell me please?

well as i studied,
E is energy, m is mass of particle and c is the speed of light which is constant.

in this manner e is directly proportional to the m.
i.e. every single particle can be changed into energy.

Thus this formula gives the meaning that nothing in the world can be created or destroyed, it is just changed from one state to another.

I hope that makes it clear.