  The discovery of the quantised Hall effect, and its subsequent topological
explanation, demonstrated the important role topology can play in determining
the properties of quantum systems. This realisation led to the development of
topological band theory, where, in addition to band index and quasimomentum,
Bloch bands are also characterised by a set of topological invariants. This
topological theory can be readily extended to periodically-driven systems. In
the limit of fast driving, the topology of the system can still be captured by
the topological invariants used to describe static systems. In the limit of
slow driving, however, situations can arise where standard topological
invariants are zero, but yet, topologically protected edge modes are still
observed. These "anomalous" topological edge modes have no static analogue, and
are associated with a distinct topological invariant, which takes into account
the full time-evolution over a driving period. Here we demonstrate the first
experimental observation of such anomalous topological edge modes in an
ultrafast-laser-inscribed photonic lattice. This inscription technique allows
one to address each bond of a lattice independently and dynamically, generating
a rich band structure with robust anomalous chiral edge modes and the potential
for perfectly localised bulk states.
