This course explores the concept of resilient aging in the built environment, addressing two interconnected dimensions: the aging of people and the aging of cities and buildings that no longer meet contemporary needs. By reframing aging as both a challenge and an opportunity, the course examines strategies to understand, intervene in, and transform the built environment to better support evolving societal needs. Rather than relying solely on top-down design and planning approaches, this class emphasizes bottom-up interventions and participatory design methods to understand and engage vulnerable populations. The course approaches aging through three interrelated topics: the adaptive reuse and activation of aging urban infrastructure, the retrofitting of aging suburbs through innovative housing and real estate models, and the application of advanced urban technologies to analyze and understand resident behavior in aging and informal settlements. These topics aim to provide students with the knowledge and tools to reimagine the built environment, fostering resilience and equity for aging populations and the spaces they inhabit. The first half of each session will be lectures, providing foundational knowledge and sharing related research works, while the second half will be dedicated to discussions, allowing students to engage with the materials and collaborate on the topics.