The Lisbon Biodiversity Trail consists of a series of interconnected points identified as being of interest for observing species of flora and fauna.The Biodiversity Trail seeks to highlight the importance and influence of the Tagus River and the ecosystem formed by the Monsanto Forest Park (a green area covering approximately 900 ha), as a starting point for exploring the great diversity of flora and fauna that can be observed in Lisbon. It is a walking route—which can also be traveled by bicycle—taking visitors through places as diverse as the Belém waterfront and its gardens, the Alto de Santo Amaro Chapel, the Avelar Brotero Garden, the Keil do Amaral Amphitheater, Restelo and its lawns, and various landscaped squares featuring numerous tree species classified as being of Public Interest.The vegetation typical of Mediterranean and Atlantic ecosystems is found in the woodlands, groves, and meadows, with its presence largely due to plantings but also to natural regeneration processes. On private farms, in olive groves, vegetable gardens, and urban orchards, one finds species representative of the cultural flora. There is also an enormous diversity of flora found in the various botanical gardens, where exotic and ornamental species take center stage, particularly due to their scientific interest and historical value, serving as an indication of the region’s ecological potential.This biological richness is also reflected in the diversity of native fauna, which finds habitats and ecological niches in Lisbon as varied as the riverside area, forested areas—including clearings and meadows—and even urban parks and gardens. This allows for the presence of resident species, which inhabit the region year-round, as well as migratory species—whether those that spend the winter (winter visitors) or the summer (summer visitors) here, or those that use the region solely as a resting and feeding stopover during their migratory route. Since a circular route of approximately 14 km is proposed, it is considered ideal to begin at the Módulo Ambiente, the municipal service center for environmental affairs, located on Rua Vieira Portuense in Belém.