Also known by its acronym: CAX, this is a military training exercise that combines elements of various combat and support groups. The USMC holds one or more of these each year (usually in the summer) at the MCAGCC at Twentynine Palms, CA.
These combat exercises usually consist of elements of the following:
Daytime temperatures in
Twentynine Palms, where these are held, often reach 110 - 125 degrees F in the shade.
Desert floor temperatures are often 20 degrees higher, so these exercises are what keeps the
Marine Corps acclimatized to
desert operations.
A common sight on these exercises is to see Marines carrying flaxen water bags slung over a shoulder. These desert water bags, which are made of porous woven flax, hold from 1 to 2 quarts, depending on size, and use evaporation to keep the contents surprisingly cool.
It is not uncommon to see MUCH unexploded ordnance sticking out of the sand in Twentynine Palms, so Marine EOD teams are constantly on call for safe disposal of these bombs by remote detonation.
(I was stationed at Twentynine Palms during Desert Storm back in 1990 and 1991 as a part of 1st FSSG forward detachment)