I'm interested in Roof Gardens

I'm interested in Roofgarden.In Japan ,there are many roofgardens.I want to know the roofgardens in other country.In japan some of them is greenery roof.and others are garden on the building.Recently ,gardentype have become rich variety.

I'm interested in roof gardens.  In Japan, there are many foor gardens.  I want to know about roof gardens in other countries.  In Japan some of these gardens are greenery on the roof and others are gardens on the building (top?)  Recently there is a large variety in the types of roof gardens.