To become a U.S. Army Ranger, the country's finest soldiers willingly submit themselves to what many would consider a form of torture for just over two months. A big part of the strenuous physical test is just staying awake. They run combat missions 20 hours a day while consuming just enough calories to keep from passing out; a grueling test of endurance that forces Ranger School students to go to extremes just to keep their eyes open. Some even resort to putting tabasco sauce in their eyes.
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Ranger School has been called the toughest combat course in the world. And by the end of it, nearly 75 percent of the soldiers who went in will have dropped out, due to fatigue, injury or failure. In April 2015, nineteen women and 380 men were pre-screened for the program. In August 2015, two women and 94 men completed the 62-day course.
As of August 21, 2015, these two women -- U.S. Army First Lieutenant Kirsten Griest (seen here at left participating in combatives training at Fort Benning, and First Lieutenant Shaye Haver (seen here at right taking part in Mountaineering training on Mount Yonah in Cleveland) -- are the first women to ever graduate from the daunting U.S. Army Ranger school.
They still can't serve in the 75th Ranger Regiment, but that reality may change soon. Their graduation has helped end questions about whether women can serve as combat leaders. Consequently, the Pentagon is poised to open new roles, including elite Navy SEALs, to women in the coming months.
To become an army ranger, students must go on long marches and patrols carrying rifles, rucksacks and other gear, weighing upwards of 100 pounds.
Kristen Griest, a military police officer from Connecticut, and Lt. Shaye Haver, an Apache helicopter pilot from Texas are both officers and West Point graduates. Several of their male classmates, who joined them at a news conference on August 20, 2015, admitted that they were initially skeptical about whether female soldiers could handle those tasks; but quickly realized the women were "physical studs." One male student even noted that the only reason he made it through Ranger School himself was because Lt. Haver jumped in to help him carry some of his load when he was struggling.
The worm pit
Ranger students must negotiate a shallow, muddy obstacle, called the "worm pit," where they crawl underneath knee-high barbed wire several times, on both their backs and their stomachs.
Rope crawl 35 feet up
Students must overcome any fears of height or water by walking calmly across a log, suspended thirty-five feet in the air, then transitioning to a rope crawl.
They must then plunge into the pond below and ditch all of their equipment before surfacing.
70-foot water plunge
Each student must also climb to the top of a 70-foot tower along the side of Victory Pond and plunge into the water below, holding onto a pulley attached to a suspended cable.
An Army Ranger's primary mission is to engage in close combat direct fire battle, but Ranger School also trains them in the original method of combat: hand-to-hand.
US Army Rangers must demonstrate parachute jumps and a helicopter extraction hooked on a rope in Fort. Benning, Georgia.
Chin ups from a dead hang
In the first phase of Ranger School, students must perform a minimum of six chin-ups from a dead hang with absolutely no body movement.
Ranger students must complete a 12-mile tactical march, which entails walking quickly in full gear while also carrying a 35 pound rucksack, in under three hours.
The mountain phase of Ranger School combines the physical hardships of military mountaineering tasks with the mental hardships of feeling like they're in the middle of nowhere. In the winter months, temperatures at Camp Merrill near Dahlonega, Georgia (where the mountain phase takes place) drop so low that students often develop frostbite.
In 1995, four students died from hypothermia. In total, 27 lives have been lost at Ranger School, since it began in 1950.
Rangers must also demonstrate repelling by walking down a 90-degree tower at the US Army Infantry School in Fort Benning, Georgia.
The Darby Queen Obstacle Course is made up of 26 obstacles, scattered over nearly a mile of rolling Georgia terrain. It forces students to climb over three-story structures and crawl through mud trenches that are covered in barbed wire. What's more, Ranger instructors litter the course, adding psychological stress to the physical demands of the course.
In the swamps of Florida and the mountains of Georgia, Ranger School tests a student's strength on everything from PT, swim tests and land navigation exercises, to mountaineering tests and mock patrols.
To pass, students must receive a physical training score of 240 or higher. That means they must score at least an 80 percent on each obstacle.
Ranger School is open to students from all military specialities (Army, Air Force, Marine Corps, Coast Guard, etc.). It even allows recruits from foreign military services. Most Ranger School students, however, come from the U.S. Army's Infantry Basic Officer Leadership Course.
More photos: America's elite special forces