A spacetime whose invariant classification requires the fifth covariant derivative of the Riemann tensor

We present the first example of a metric whose invariant classification req uires the fifth covariant derivative of the Riemann tensor. The existence o f this metric raises the known practical bound for invariant classification s, reconciles the theoretical and practical upper limits for invariant clas sifications of Petrov type N spacetimes, and brings the practical limits fo r invariant classifications to within one of the theoretical limits for a s pacetime in general.