QCD is the fundamental theory of the strong interaction. It accounts for the nuclear force/energy and the majority of the mass of the non-dark universe. Moreover, it plays an important role in the evolution of the early universe, from the quark-gluon phase to the hadron phase. Starting from the QCD lagrangian with a handful of parameters such as the bare quark masses and the Lambda_QCD, lattice QCD can give precise predictions (which can be systematically improved) for most physical quantities resulting from the strong interaction. In this talk, I give an overview of the state-of-the-art simulations of lattice QCD with physical (u/d,s,c) quarks, and present the first physics results of the hadron mass spectrum and the topological susceptibility from Nf=2+1+1 lattice QCD with physical domain-wall quarks.