The CTAO (Cherenkov Telescope Array Observatory) will be the world’s largest and most sensitive observatory for gamma-ray astronomy. With more than 60 telescopes located in the northern and southern hemispheres, the CTAO will explore the very high-energy Universe within an unprecedented energy range (20 GeV – 300 TeV) and accuracy. Based on its commitment to Open Science, the CTAO will be the first observatory of its kind to operate as an open, proposal-driven observatory providing public access to its high-level science data and software products.   The CTAO requires the collaboration and investment of a wide international network of countries and contributors. The Observatory is supported financially by a growing list of shareholders, which includes more than ten countries and an intergovernmental organisation. More than 1,500 people working in different international teams contribute to the implementation of the CTAO, as well as to its scientific, software and hardware development. The CTAO was included in the 2008 roadmap of the European Strategy Forum on Research Infrastructures (ESFRI) and promoted to a Landmark project in 2018. It is one of the “Magnificent Seven” of ASPERA’s European strategy for astroparticle physics and a top-ranked priority amongst new ground-based infrastructure projects in ASTRONET’s “Roadmap 2022-2035: A Strategic Plan for European Astronomy.”