Malmo, Sweden is building a Fair and Exhibition Centre that will have the country's largest green roof. Erik Giudice Architects created the winning design. The property will be developed by Midroc Property Development.
According to World Architecture News, the building is:
"...approximately 19,000 sq m comprises exhibition halls, conference rooms, a restaurant, offices, commercial and support spaces."
The design allows for the addition of an additional 5,000 sq m for mixed use, including housing. Further, the structure will be accessible by a rail link between Malmo and Copenhagen.
Green Roof.se, the Augustenborg’s Botanical Roof Garden is 9,500 sq m. It covers several buildings and open to the public. I highly recommend reviewing the site via the link I posted above, as it is an aggressive and very interesting project.
If you are looking for a city to visit with green roofs, put Malmo on your list!