Montreal Olympic Stadium and surrounding structures, are but a few notable examples of the city's 20th-century architecture. Pavilions designed for the 1967 International and Universal Exposition, popularly known as Expo 67, featured a wide range of architectural designs. Though most pavilions were temporary structures, several have become landmarks, including Buckminster Fuller's geodesic dome U.S. Pavilion, now the Montreal Biosphere, and Moshe Safdie's striking Habitat 67 apartment complex. The Montreal Metro has public artwork by some of the biggest names in Quebec culture. In 2006 Montreal was named a UNESCO City of Design, only one of three design capitals of the world
Geodesic deviation "geodesic". The "geodesic deviation equation" relates the Riemann curvature tensor to the relative acceleration of two neighboring geodesics. In differential geometry, the geodesic deviation equation is more commonly known as the Jacobi equation. To quantify geodesic deviation, one begins by setting up a family of closely spaced geodesics indexed by a continuous variable "s" and parametrized by an affine parameter τ. That is, for each fixed "s", the curve swept out by γ(τ) as τ varies is a geodesic. When considering the geodesic of a massive object, it is often convenient to choose τ to be the object's proper time.