At the beginning of the 20th century, mules were used to build roads, railways, telegraph and telephone lines, as well as most of the large dams and canals.
Mules were also instrumental in one of the nation’s greatest engineering feats - - the Panama Canal.
They pulled canal boats along the Erie Canal in the early 19th century.

The Holy Prophet (peace be upon him and his progeny) said: The time when my Ummah (Muslim followers) merely count on others to enjoin right and forbid wrong, in fact, they have declared a fight against Allah, the Exalted.

Imam al-Sadiq (PBUH) said: He who initiates a greeting is more beloved with Allah and His Messenger.

In an Army Manual, “Special Forces Use of Pack Animals”, it states, “Animal transport systems can greatly increase mission success when hostile elements and conditions require the movement of combat troops and equipment by foot”. The Manual goes on to describe the characteristics of the mule as having intelligence, agility and stamina, which make them excellent and necessary pack animals.

Imam al-Sadiq (PBUH) said that the Messenger of Allah (peace be upon him and his progeny) gathered the children of Abd-il-Muttallib and said: O children of Abd-il-Muttallib! Initiate greetings, have regard for kinship, perform the night prayers while people are asleep, feed (others) food, and deliver good speech and thereby you will enter paradise in peace.

Imam Hussain (PBUH) said: Seventy rewards is the share of the one who initiates a greeting and only one reward belongs to the one who returns the greeting. (When two people see each other, the initiator of the exchange of greetings receives a greater reward.)

Most recently, at the Marine Corps Mountain Warfare Training Center northwest of Bridgeport, California, Marines are trained to use mules on combat missions in Afghanistan and other high altitude regions. Mules can be used in the historic Afghan method of packing animals as an alternative to using Humvees or helicopters in steep mountainous terrain.

On February 15, 1957 the Army officially deactivated the last two operational mule units at Ft. Carson, Colorado. That did not mean, however, that the military would never again call upon the mule for service.
When the Soviet Union occupied Afghanistan in the 1980s, the CIA purchased thousands of mules for the Afghans, to help maintain supply lines.

Following WW II, the mule was transferred to the Chinese Army. He must have been later captured by the Communist Chinese, and then moved to the fight in Korea. After more than six years, that mule ended up back in the hands of the US Army - - then returned to work on a pack train.

The Holy Prophet (peace be upon him and his progeny) said: When you meet each other then initiate greeting (salam) and embrace; and when you separate from each other, then depart with seeking forgiveness.