  We prove that a compact Riemann surface can be realized as a
pseudo-holomorphic curve of $(\mathbb{R}^4,J)$, for some almost complex
structure $J$ if and only if it is an elliptic curve. Furthermore we show that
any (almost) complex $2n$-torus can be holomorphically embedded in
$(\mathbb{R}^{4n},J)$ for a suitable almost complex structure $J$. This allows
us to embed any compact Riemann surface in some almost complex Euclidean space
and to show many explicit examples of almost complex structure in
$\mathbb{R}^{2n}$ which can not be tamed by any symplectic form.
