Spherical geometry other geometric concepts are defined as in plane geometry, but with straight lines replaced by great circles. Thus, in spherical geometry, angles are defined between great circles, resulting in a spherical trigonometry that differs from ordinary trigonometry in many respects; for example, the sum of the interior angles of a triangle exceeds 180 degrees. Spherical geometry is "not" elliptic geometry, but is rather a "subset" of elliptic geometry. For example, it shares with that geometry the property that a line has no parallels through a given point. Contrast this with Euclidean geometry, in which a line has one parallel through
Circular Quay end of Sydney Cove. Circular Quay increasingly became a tourist destination in its own right. Between 1971 and 1989, Colonial Mutual Life acquired land along Circular Quay for a large scale development. The initial, highly controversial design, was revised after the intervention of Prime Minister Paul Keating. In return for reducing the height of the building and adding a colonnade to facilitate public access, the development was permitted to extend further towards the foreshore, with the design finalised in 1992. In 1984, Lionel Todd (Sydney Opera House Stage 3 Architect), proposed his semi-circular quay concept to enhance views of the