geometry, a monogon, also known as a henagon, is a polygon with one edge and one vertex. It has Schläfli symbol {1}.- Moscow (Wikipedia)
Moscow is the capital and largest city of Russia. The city stands on the Moskva River in Central Russia, with a population estimated at over 13 million residents within the city limits, over 18.8 million residents in the urban area, and over 21.5 million residents in its metropolitan area. The city covers an area of 2,511 square kilometers (970 sq mi), while the urban area covers 5,891 square kilometers (2,275 sq mi), and the metropolitan area covers over 26,000 square kilometers (10,000 sq mi). Moscow is among the world’s largest cities, being the most populous city in its entirety in Europe, the largest urban and metropolitan area in Europe, and the largest city by land area on the European continent.
- Digon (Wikipedia)
In geometry, a bigon, digon, or a 2-gon, is a polygon with two sides (edges) and two vertices. Its construction is degenerate in a Euclidean plane because either the two sides would coincide or one or both would have to be curved; however, it can be easily visualised in elliptic space. It may also be viewed as a representation of a graph with two vertices, see “Generalized polygon”.