This lecture discusses the importance of individual and collective actions in achieving sustainability, focusing on the Sustainable Development Goals (SDGs) and the Millennium Development Goals (MDGs). The instructor begins by defining individual actions, such as commuting by bicycle, and contrasts them with collective actions that require organization, like building more affordable housing. The lecture highlights the success of the Montreal Protocol as a prime example of effective international collective action against ozone-depleting substances. The instructor emphasizes the need for both individual and collective efforts to address environmental challenges. The discussion then shifts to the MDGs, which aimed to eradicate extreme poverty and hunger, and the subsequent SDGs that expanded on these goals. The instructor presents data showing significant progress in reducing extreme poverty and improving education, particularly for women. The lecture concludes with a call to action, stressing the necessity of confronting power structures that hinder collective efforts to combat climate change and promote sustainability.