The sculpture garden atop the Grohmann Museum is more than an extension of the Man at Work art collection. The roof is a Green Roof — an energy-saving and environmentally friendly alternative to a conventional rooftop. The plant and grass-covered roof keeps the building cooler in the summer, saves energy and extends the useful life of the roof. Rainwater is also trapped in the plantings, reducing the amount of storm water runoff that enters the city’s sewer system.