  Physics interpretation of the ``magic'' baseline, $L_{magic}$, that can play
important role in future oscillation experiments is given. The ``magic''
baseline coincides with the refraction length, $l_0$. The latter, in turn,
approximately equals the oscillation length in matter at high energies.
Therefore at the baseline $L = l_0$ the oscillation phase is $2\pi$, and
consequently, the ``solar'' amplitude of oscillations driven by $\theta_{12}$
and $\Delta m^2_{21}$ vanishes. As a result, in the lowest order (i) the
interference of amplitudes in the $\nu_e - \nu_\mu$ $(\nu_\tau)$ transition
probability is absent; (ii) dependence of the probability on the CP-phase,
$\delta$, as well as on $\theta_{12}$ and $\Delta m^2_{21}$ disappears.
Corrections to the equality $L_{magic} = l_0$ are estimated. Effect of changing
density is considered and two new magic trajectories are identified for
neutrinos that cross the core of the Earth. Other magic baselines associated
with zeros of the atmospheric amplitude are discussed.
