Which sustainable innovation was first implemented by architect William McDonough's firm in their pioneering 'Cradle to Cradle' approach to architectural design?

The architecture industry has been rapidly evolving to incorporate sustainable practices and eco-friendly designs. Many leading architectural firms have implemented groundbreaking sustainability initiatives that have transformed how buildings interact with their environments. This trivia question tests your knowledge about a significant sustainable architecture innovation that has gained recognition in the industry.

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Material Passports - documenting building materials for future reuse
Smart Glass Windows - automatically adjusting transparency based on sunlight
Vertical Gardens - integrating plant life into building facades
Thermal Mass Flooring - absorbing heat during day and releasing at night