  What is the real nature of pulsars? This is essentially a question of the
fundamental strong interaction between quarks at low-energy scale and hence of
the non-perturbative quantum chromo-dynamics, the solution of which would
certainly be meaningful for us to understand one of the seven millennium prize
problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute.
After a historical note, it is argued here that a pulsar is very similar to an
extremely big nucleus, but is a little bit different from the {\em gigantic
nucleus} speculated 80 years ago by L. Landau. The paper demonstrates the
similarity between pulsars and gigantic nuclei from both points of view: the
different manifestations of compact stars and the general behavior of the
strong interaction.
