We show that the Hall algebra of the category of coherent sheaves
on a weighted projective line over a finite field provides a
realization of the (quantized) enveloping algebra of a certain
nilpotent subalgebra of the affinization of the corresponding
Kac-Moody algebra. In particular, this yields a geometric
realization of the quantized enveloping algebra of elliptic (or
$2$-toroidal) algebras of types $D_4^{(1,1)}$, $E^{(1,1)}_6$,
$E^{(1,1)}_7$, and $E_{8}^{(1,1)}$ in terms of coherent sheaves on
weighted projective lines of genus one or, equivalently, in terms
of equivariant coherent sheaves on elliptic curves.