In the early universe, matter and antimatter were created in nearly equal amounts. The Sakharov conditions (1967) for generating a net baryon number are: (1) baryon number violation, (2) C and CP symmetry violation, and (3) departure from thermal equilibrium. The observed asymmetry is η = (n_B − n_B̄)/n_γ ≈ 6×10⁻¹⁰ — for every billion antimatter particles there were a billion-and-one matter particles. After annihilation, the residual matter is everything we see. The Standard Model has too little CP violation; beyond-SM physics (leptogenesis, electroweak baryogenesis) is needed to explain our existence.