Abstract: In 2023, several international pulsar timing array teams independently announced evidence for a nanohertz gravitational wave background. This implies that a new gravitational wave observational window will become available soon. The Parkes Pulsar Timing Array was the first pulsar timing array experiment to have made pioneering contributions in developing advanced instrumentation for pulsar observations, efficient data reduction software, methods for pulsar timing noise analysis, and gravitational wave searches. This article presents an overview of the Parkes Pulsar Timing Array project, its unique contribution to the field, and latest research results.