Perched between stands of eucalyptus that have replaced the indigenous vegetation (oaks, pines and olive trees), you can breathe in the scent of the hills and be watchful for the local fauna.
These places, almost hidden from the unobservant, can be reached by narrow paths. From Fort Simplício, the city of Lisbon, the 25th April suspension bridge or the Pena Palace in Sintra seem surprisingly close.
