Electron, proton, and their antiparticles consist of an electromagnetic field and a constituent that creates it. The simplest constituent is a one-dimensional circular current loop. The elementary charge is homo-geneous¬ly distributed over its circumference and rotates at a constant velocity. The charge creates an electrostatic field. Its rotation represents a current that creates a magnetic field. Balance between the electric and magnetic forces ensures stability. This requires a marginal radial extension of the loop that makes the particle two-dimensional. In the near vicinity of two equal concentric current loops the axial attractive magnetic force compensates for the axial repelling electrostatic force. This discovery explains the weak (electron) and strong (proton) nuclear forces. Electron and proton have normal magnetic moments. The measured "anomalies" indicate the existence of a hidden rotational kinetic energy caused by rotation of the annular particle mass. So, there are four natural forces: electric, magnetic, kinetic, and gravitational. This knowledge makes the search for the Grand Unified Theory (GUT) trivial. The discovered rotational energy affects Einstein’s and Planck’s energy equations and leads to the exact calculation of the Lamb shifts and the binding energies of the hydrogen-like atoms. The theory predicts stable multiple particles and explains the Cooper Pair. For the first time the Planck mass and the gravitational constant are analytically calculated at high accuracy.