In today's lecture, we'll discuss the impact of urban green spaces on mental health. Recent studies show that even small parks can reduce stress levels significantly. However, the key factor is not the size, but the quality of the greenery, including the variety of plants and the presence of water features. For instance, a study in Melbourne found that residents living near well-maintained gardens reported a 20% decrease in anxiety. Interestingly, the effect was stronger for people who actively participated in community gardening, rather than just passive viewing. So, while access is important, engagement seems to amplify the benefits.