Digital twins provide a powerful framework for creating high-fidelity virtual representations of real environments, enabling new forms of analysis, interaction, and decision-making. This talk will introduce the key principles behind building robust digital twins from real-world data, including capture workflows, reconstruction methods, and scalability considerations. I will present several use cases across domains such as cultural heritage, industrial environments and operations, virtual production, and interactive or gamified applications, illustrating how digital twins deliver measurable value in diverse contexts. The session will highlight how these models can integrate with computational pipelines, opening the door to applications that require high realism and scientific reliability. This general overview will establish a foundation that accommodates deeper exploration of specific applications during the live presentation.