  A bubble of nothing is a spacetime instability where a compact dimension
collapses. After nucleation, it expands at the speed of light, leaving
"nothing" behind. We argue that the topological and dynamical mechanisms which
could protect a compactification against decay to nothing seem to be absent in
string compactifications once supersymmetry is broken. The topological
obstruction lies in a bordism group and, surprisingly, it can disappear even
for a SUSY-compatible spin structure. As a proof of principle, we construct an
explicit bubble of nothing for a $T^3$ with completely periodic
(SUSY-compatible) spin structure in an Einstein dilaton Gauss-Bonnet theory,
which arises in the low-energy limit of certain heterotic and type II flux
compactifications. Without the topological protection, supersymmetric
compactifications are purely stabilized by a Coleman-deLuccia mechanism, which
relies on a certain local energy condition. This is violated in our example by
the nonsupersymmetric GB term. In the presence of fluxes this energy condition
gets modified and its violation might be related to the Weak Gravity
Conjecture. We expect that our techniques can be used to construct a plethora
of new bubbles of nothing in any setup where the low-energy bordism group
vanishes, including type II compactifications on $CY_3$, AdS flux
compactifications on 5-manifolds, and M-theory on 7-manifolds. This lends
further evidence to the conjecture that any non-supersymmetric vacuum of
quantum gravity is ultimately unstable.
