Forestiere Underground Gardens are located in Fresno, California.
In early 1900s Sicilian emigrant Baldasare Forestiere started the project- complex of underground rooms, gardens and passages. It took him 40 years of excavation by hand to complete it!
Neglected and vandalised for years, gardens are being gradually restored by descendants of an original owner-visioner. Interesting place to visit.
Apparently this site is still visited by engineering students today because of the way in which the passages are used to funnel air from room to room using both the predominant directions the wind blows and the cooling effect of the underground passages themselves. Amazing!