Due to climate and geological characteristics, they created a ecosystem in the urban patch of Lisbon (and surrounding municipalities).

Its main purpose is to make visitors aware of the many variables of the environment, for instance, geology, climate, flora, and fauna.

In the 1930s, the increasing demand for construction areas led Duarte Pacheco, the then Minister for the Public Works of Portugal, to resuscitate an idea from 1868: the reforesting of the then practically bare Serra de Monsanto.

Architect Keil do Amaral presented the first complete plan for the park, including leisure and sports areas, some of which still exist.

The Monsanto Park Circuit, a 5.44 km (3.38 mi) race track, hosted the 1959 Formula One Portuguese Grand Prix.