The US Army's Brigade Combat Teams (BCTs), combined with its maneuver combat training centers, form the building blocks of the service.

The US Army is built around BCTs, which are stand-alone and self-sufficient tactical units that train and deploy together on a rotating basis. They have been described as "the basic, combined-arms building block of the Army."

The service has 32 active-duty BCTs and the 27 Army National Guard BCTs. Each one consists of 4,000-4,700 personnel and is usually commanded by a colonel.

There are three types of BCTs: Stryker (SBCTs), Infantry (IBCTs), and Armored (ABCTs). The army has 14 active IBCTs, 11 ABCTs and seven SBCTs.

The National Guard's BCTs include 20 IBCTs, five ABCTs and two SBCTs.

Each IBCT and ABCT is made up of infantry or armor/mechanized infantry battalions, a cavalry squadron, a field artillery battalion, a brigade engineer battalion and logistics support battalion.

SBCTs comprise three infantry battalions, a cavalry squadron, a field artillery battalion, a brigade support battalion, a brigade engineer battalion, a military intelligence company, an engineer company, a signal company, an antitank company and a headquarters company.

Maneuver combat training centers

The Army operates three maneuver combat training centers dedicated to preparing BCTs for combat.

They include the National Training Center at Fort Irwin, California; the Joint Readiness Training Center at Fort Johnson, Louisiana; and the Joint Multinational Readiness Center in Bavaria, Germany.

All active-duty and Army National Guard BCTs prepare at one of these maneuver training centers right before they are scheduled to deploy.

Each one typically spends about a month at one of the centers, with an 18-day rotation into the training area, also known as the "maneuver box." The maneuver box is a live-fire training area that simulates combat operations against a world-class opposing force.

The box is specifically designed to mimic the actual mission a brigade will have on its deployment. Crews in the box conduct both defensive and offensive operations, scanning for threats and repelling enemy attacks.

These centers aim to create a standardized force of leaders and units that are equally skilled and equally trained across offense, defense and stability operations.

The rigorous training of the US Army's BCTs has been noted by both allies and foes.

As one French soldier who fought alongside the US Army in Afghanistan noted in a blog post in 2008: "...the American soldier is no individualist. The team, the group, the combat team are the focus of all his attention."