Mt. Lykavittos (Lykabettus)

This peak right near the center of the city is a favorite walking place for Athens, with roads and path winding up, and also a cable car. The slopes are covered with mostly pine trees, with a variety of rock plants, and some good views of migrating birds. You can also see Saronic Gulfs islands on a clear day from up here.

Nymphon Hill

Just south of the Acropolis, this hill has lovely spring flowers and bushes, as well as some olive, carob and pine trees. Birds fly over this hill in large numbers, and there are songbirds in the trees and scrub, and butterflies of several kinds.