Why is there grass on the roof of Parliament House?

There is grass on the roof of Parliament House because the building was designed to blend with the environment. It also symbolises that the government is never above the people. 

Australian Parliament House was built into Capital Hill. This reflects Walter Burley Griffin’s vision for Canberra, which integrated built and natural environment. One million cubic metres of earth and rock were removed during the building process. Once complete, the earth was placed on the roof and covered with grass to recreate the shape of the hill. Visitors can walk on the grass on the roof of Parliament House. This symbolises that the people are above the government.