text: Team Operations
  City Cores and Outlying High-Rise Areas—Typical city cores consist mostly of high-rise
  buildings that can vary greatly in height. More modern buildings often have more space
  between them than that do the buildings in older city cores. This open construction style is
  more prevalent in outlying high-rise areas than in city cores. Streets generally form rectangular
  patterns.
  Commercial Ribbons—These rows of stores, shops, and miscellaneous structures are built on
  either side of the major (at least 25 meters wide) streets that run through built-up areas. These
  structures are uniformly two or three stories tall.
  INSERTION AND EXTRACTION
  4-235. Leaders must consider the distance of the insertion or extraction, and the training of all team
  members. They consider support assets, their own experience, and internal and external assets. All types
  of insertion and extraction means available in other environments are still viable in an urban
  environment; however, considerations for their use may be different. For example, the use of
  nonstandard tactical vehicles may be a good insertion and extraction platform in urban areas during
  stability operations. Subterranean corridors such as sewers, subways, underground tunnels, or drainage
  systems can be used with great effectiveness.
  EVALUATION
  4-236. When a LRS team evaluates urban terrain, it considers the following factors:
  Observation
  4-237. Buildings on the edge of a city generally offer better observation than those inside. There, tall
  buildings with numerous windows often offer the best observation, especially if the buildings have
  spaces between them.
  Avenues of Approach
  4-238. The best way to enter a building is from the top. Therefore, the most important avenue of
  approach is one that quickly leads to the top from fire escapes, drainpipes, or adjacent buildings.
  Key Control Points
  4-239. Key control points in a building include entrances, hallways, and stairs. Whoever controls these
  controls the building.
  Doors and Fire Barriers
  4-240. These are common in commercial buildings. They become obstacles when closed or secured.
  Furniture and appliances can also become obstacles.
  Cover and Concealment
  4-241. Buildings with brick walls and a few narrow windows balance cover and concealment. Roofs
  provide little protection—lower floors offer LRS teams better protection than do areas directly under the
  roof. Additionally, floor layouts with many small rooms offer more protection than those with
  larger rooms.
  Intercity Distribution of Building Types
  4-242. Leaders can generally determine the layout of a city by the distribution of the buildings within
  the city. In built-up areas, mass-construction buildings (modern apartments and hotels) are the most
  common structures. They comprise two-thirds of the total area, and they are usually constructed of brick.
  Steel and concrete-framed multistory buildings comprise the city's core area, its most valuable land. As
  centers of economic and political power, they have potentially great military significance. Open spaces,
  such as parks, athletic fields, and golf courses, comprise about 15 percent of the average city's area. Most
  of this 15 percent is suitable for air assault or Airborne operations. However, approaches to these areas
  may have obstacles such as tall buildings, trees and wires, and should be carefully considered during