  We prove experimentally the predicted existence of a three-qubit quantum
state with genuine multipartite entanglement which can be certified solely from
its separable two-qubit reduced density matrices. The qubits are encoded into
different degrees of freedom of a pair of correlated photons and the state is
prepared by letting the photons to propagate through a linear optical circuit.
The presence of genuine multipartite entanglement is verified by finding
numerically a fully decomposable entanglement witness acting nontrivially only
on the reductions of the global state. Our result confirms viability of
detection of emerging global properties of composite quantum systems from their
parts which lack the properties.
