  We give a new proof of Fejes T\'oth's zone conjecture: for any sequence
$v_1,v_2,...,v_n$ of unit vectors in a real Hilbert space $\mathcal{H}$, there
exists a unit vector $v$ in $\mathcal{H}$ such that \begin{equation*}
  |\langle v_k,v \rangle| \geq \sin(\pi/2n) \end{equation*} for all $k$. This
can be seen as sharp version of the plank theorem for real Hilbert spaces. Our
approach is inspired by Ball's solution to the complex plank problem and thus
unifies both the complex and the real solution under the same method.
