The paper provides a comprehensive overview of the 6G vision, technical requirements, and application scenarios, building on existing literature and research. It highlights the challenges and limitations of 5G, such as global coverage, ultra-high data rates, ultra-low latency, ultra-dense connections, high-precision positioning, and energy efficiency. The paper discusses the global efforts and developments in 6G research, including initiatives from various countries and organizations. It critically evaluates the 6G network architecture and key technologies, proposing a novel 6G network architecture. The paper also reviews existing 6G testbeds and verification platforms, detailing their components and functionalities. Additionally, it identifies future research directions and open challenges, emphasizing the importance of addressing security, intelligence, and endogenous security in 6G networks. The paper concludes with lessons learned from the critical appraisal of the literature and a summary of the key findings.The paper provides a comprehensive overview of the 6G vision, technical requirements, and application scenarios, building on existing literature and research. It highlights the challenges and limitations of 5G, such as global coverage, ultra-high data rates, ultra-low latency, ultra-dense connections, high-precision positioning, and energy efficiency. The paper discusses the global efforts and developments in 6G research, including initiatives from various countries and organizations. It critically evaluates the 6G network architecture and key technologies, proposing a novel 6G network architecture. The paper also reviews existing 6G testbeds and verification platforms, detailing their components and functionalities. Additionally, it identifies future research directions and open challenges, emphasizing the importance of addressing security, intelligence, and endogenous security in 6G networks. The paper concludes with lessons learned from the critical appraisal of the literature and a summary of the key findings.