The concept of Digital Twins of the Earth is at the heart of the recent and ambitious European Commission's initiative, named Destination Earth -also known as DestinE. This initiative was introduced by the EU data strategy, as a concrete action contributing to realize the Common European Green Deal data space, with the aim of using the major potential of data in support of the Green Deal priority actions on climate change, circular economy, zero pollution, biodiversity, deforestation and compliance assurance. DestinE will "bring together European scientific and industrial excellence to develop a very high precision digital model of the Earth". This groundbreaking initiative will offer a digital modelling platform to visualize, monitor and forecast natural and human activity on the planet in support of sustainable development thus supporting Europe's efforts for a better environment as set out in the Green Deal. Destination Earth will contribute to Shaping Europe digital future, according to the EU digital strategy and noticeably its principles on ethics, democracy, fairness and open autonomy. The present document introduces a set of principles and patterns to be applied by the Destination Earth ecosystem in order to match its stakeholders' and users' needs and requirements. They have been captured and articulated in a set of significant use cases, analysed in a previous study of the JRC. The presented well-defined principles are important to realize a flexible, evolvable, and viable Destination Earth ecosystem. Then, the document provides an architectural description of the ecosystem, applying a set of international standards for the definition of complex system architectures. Specific sections are dedicated to present and discuss the different concerns that characterize the Destination Earth system: the business, information, functional, engineering, and technological viewpoints. Then, a technological architecture, based on a virtual cloud platform enabled by a multi-cloud environment, is discussed. Finally, the results of a proof-of-concept implementation of such technology architecture are reported and discussed.
