Abstract
Circle is one of the most used curves in architecture. Parts of the circles can be found in the arches of the vaults, as the supporting and decorative elements of the window holes, in the floor plan of the buildings.
In the Baroque architecture oval was very common. The article shows the concrete realizations of these curves and offers suggestions for diversifying the teaching of geometry.
At the end, it is described how to easily use GeoGebra software to explore these curves.