In a natural cleft between walls of soft tuff (volcanic rock), the Giardino della Kolymbetra is a lush garden of olive and citrus trees interspersed with more than 300 labelled species of plants and some welcome picnic tables. Managed independently by the non-profit historical preservation organisation FAI, it's a peaceful, shady spot, perfect for escaping the heat of the valley and breaking for a picnic lunch. The climb down is steep (best avoided if you've got dicky knees).

　　Daily from mid-June to September and on Saturday and Sunday from March to mid-June and from October to December, one-hour guided tours (adult/reduced €16/11) of a hypogeum (underground chamber) within the gardens are available. Booking ahead is recommended at www.agrigentosotterranea.it; the tours incorporate negotiating compact tunnels and an underground river.