Dynamic fracture mechanics is concerned with fracture phenomena for which the effects of material inertia cannot be ignored. The advent of ultra-high-speed imaging and advanced computational tools has enabled researchers to observe phenomena, such as crack branching instabilities, that classical theories could not adequately explain. This has led to a paradigm shift, reframing the dynamic crack tip not merely as a mathematical stress singularity but as a ”natural laboratory” for probing material behavior under the most extreme conditions of strain, strain rate, and energy dissipation. Consequently, the central focus has evolved from predicting failure to understanding the complex, non-equilibrium dynamics that govern it. This broader perspective has attracted interdisciplinary interest, with applications now spanning the design of advanced materials for aerospace and defense, and the modeling of geological events like earthquakes. This symposium aims to provide a forum for the exchange of knowledge and the promotion of innovation in the dynamic fracture of materials and structures. By bringing together leading researchers from the fields of experimental mechanics, theoretical modeling, and computational simulation, this event will facilitate fruitful discussions on the pressing, unresolved questions that define the frontiers of this discipline. Specifically, the following topics are of interest: • Strain-Rate Dependency of Material Properties. • The Role of Rate-Dependent Constitutive Laws, both phenomenological and physically-based. • Disentangling the Multifaceted Role of Inertia. in the context of continuum damage and phase-field models, which represent a crack by ”smearing” the damage over a finite region. This raises a fundamental question: should this region also lose its inertial mass? • Terminal Crack Velocity in Materials. • Crack Branching Instability. • High-Fidelity Measurement and Visualization (high-speed photography, dynamic photoelasticity, digital image correlation). • Uncertainty Quantification (UQ). • Advanced Numerical Formulations: cohesive zone models, extended finite element methods, phase-field models, material sink theory, peridynamics, meshfree methods. • Multiscale modeling. • Multiphysics. specifically coupled systems relevant for industrial applications.