  We present a simple spherically symmetric and regular solution of Einstein's
equations with two parameters $k$ and $M$, which matches to Schwarzschild's
solution, satisfies the weak energy conditions in the interior region and for
small $r$ behaves like the de Sitter solution. Its energy density $\rho$ and
its radial pressure $p_r$ satisfy the relation $\rho+p_r=0$. For some values of
$k/M$ the solution does not have an event horizon and the event horizon of
Schwarzschild's solution is inside the matching surface. Therefore it describes
the formation of a gravitational soliton, which is shown to be stable.
Gravitational solitons are related to dark matter. For the other values of
$k/M$ it is a regular black hole solution.
