 From the skies above Vietnam, a team of men descends from the sky to clear a landing zone behind Viet Cong positions. Miles away through the tangled undergrowth, a jungle plow rips its way to clear a battery position for the artillery. On a road that ends at the banks of an unfordable river, a team of sweating men spans the waters with a footbridge so the advancing infantry can press on. On the coastal plains near the China Sea, a team of experts searches out the hidden death so cunningly concealed by the enemy, clearing the way for convoys moving north. They work against time and in ever-present danger. In each case, the men are combat engineers. In every corner of South Vietnam, such men are writing in sweat and blood a new chapter in the saga of the Army's engineers. Men who often must fight before they can work. Whenever and wherever they're needed, they are there. With bulldozers, guns, and guts, they are continuing a proud tradition as they clear the way. Okay, move out. South Vietnam is often called the rice bowl of Asia. For more than 20 centuries, the people have worked the rice paddies of the fertile lowlands, where countless rivers and streams provide natural irrigation. But not all the wetlands are under cultivation. There are tropical swamps which never dry up, an endless sea of coarse water grasses and bogs. In this kind of country, the machines of war have trouble. For the American foot soldier, these swamps and mazes of waterways are a curse to be born, part of the job in this kind of conflict. But perhaps more important, the water barriers hinder speedy pursuit of the enemy. On high ground, tough elephant grass, bamboo thickets, and a frustrating abundance of vines and scrub brush face the soldier on foot. In the foothills of Vietnam's mountain country, the dense rainforest towers toward the sun, and beneath them is a perpetual twilight with dank, rotting vegetation underfoot. The rugged, anomite mountains form a spine which runs the length of South Vietnam from Khantum province to Saigon. Except for mountain tribes, this region has remained virtually undeveloped for hundreds of years. Into this strange land of extremes come the fighting men of the United States Army. Their mission? To seek out and defeat an enemy who uses these natural barriers as one of his most potent weapons. Help overcome these obstacles to clear the way for our fighting forces. This is the job of the combat engineer, with the tools of his trade in one hand, and the weapons of his profession in the other. Most roads in Vietnam are little more than narrow dirt trails. To our highly mobile army, the lack of sufficient overland routes poses a major problem. In this tiny republic half the size of California, every hard-surfaced highway is heavily traveled. The need for new roads through the interior wilderness is vital to the supply and support of widely scattered combat forces. For the combat engineers, the job begins with a thorough study of the terrain. A first step lies in careful study of aerial photos. Once a general knowledge of the terrain is gained, the project engineer takes to the air for a closer inspection of the area where a road is to be built. Flying repeatedly over the proposed route, he checks out such key features as heavily timbered sections, rivers to be bridged, prominent outcroppings of rock, all the natural barriers which will have to be overcome in a minimum of time. An engineer recon section goes into the area next. If there are any Viet Cong remaining in the region after recent search and clear operations, they will have to be flushed out. In the humid shadows of the jungle, enemy snipers plague the patrol, but they are silenced by the combat engineer team, and the reconnaissance mission, the job they came to do, goes on. Soon the jungle echoes to the snorting of massive diesel tractors. These powerful machines, with their special knife-like blades, give the combat engineers a high-speed method of tearing away the monarchs of the tropical forests. A ribbon of cleared land begins to appear through the wilderness to link up with existing roads far to the north. Another road is completed. The first convoy of fuel tankers moves over the mountains to resupply fighting units in Cancun province. Despite landslides, rocky cliffs, and tangled jungles, the combat engineers have opened the way for a steady, large-scale flow of food, fuel, and vital ammunition to our men in the battlefield. But the work doesn't stop there. Maintaining and repairing the road network in South Vietnam is one of the roughest tasks of the combat engineer. Many small, backcountry roads never intended for heavy truck traffic are endlessly in need of repair. If the forces of nature and the pounding of traffic don't wreck them, the Viet Cong do. Sometimes blowing up bridges will be trapping and mining, anything to deny their use to the Allied military forces. Damaged, weakened bridges are not repaired, they are replaced. Pre-measured bridge components make the job of erecting a new span a matter of days instead of weeks. Freshest time is saved when sections of a bridge are flown in by helicopter and lowered into position. The last piece is in place and no time is lost before the new bridge goes to work. Another route opens for vital movements of men and materiel. The combat engineers are trained to build a wide variety of tactical bridges as well. Lightweight foot bridges like this one provide quick passage across rivers and streams. For a more permanent structure, the steel sections of a bailey bridge may be brought up and locked together. This type of bridge can handle the heaviest military vehicles, yet with its ingenious design it can be quickly assembled. Or perhaps an armored column may come to a natural barrier just a bit too wide and deep to cross. The answer may be, once again, the combat engineers and a weird-looking device called the scissors bridge. Manoeuvring carefully into position, the artfully jointed twin roadway of high-strength steel begins to extend itself. Mounted on its own armored carrier, it can reach out like a giant, preying mantis to bridge a gap up to 60 feet wide. Its deliberate motion seems slow, but compared to the time it would take to build a bridge strong enough to carry tanks across, the scissors bridge works with priceless speed. A combat engineer locks the massive hinge point into place. Tons of armor steel can rumble across what had been an impassable obstacle and continue with its mission. Meantime, the large-scale work goes on. Existing maps of Vietnam have proved inadequate, lacking in detail, often inaccurate. Army engineers together with the Vietnamese are surveying the entire country for new maps. A thorough geodetic survey was essential to establish control. Both visual sighting techniques and electronic distance-measuring devices are used to pinpoint exact locations and elevations. At the Mobile Cartographic Unit, the engineer's expert draftsman used the compiled information to scribe the basic map on plastic sheets, one for each color in the map. This is delicate, exacting work. Recent aerial mapping photography provides another valuable tool. Scaled to match the framework established by a precise plot of the geodetic control, it is possible to plot roads, streams, shores, and other details in exact positions. Once the map is compiled and drafted, an engineer specialist in cartographic process photography makes a series of negatives of the prepared material. He will combine these into a single copy to be checked and corrected with minute care. The map will be printed by the photo offset process. A light, sensitive metal plate is exposed for each of the corrected negatives. Now the actual printing of the new map can begin. Finally, the engineers produce thousands of copies of new, exactly accurate, detailed maps. The constant battle to maintain microscopic accuracy is spurred by the engineer's knowledge that the slightest error could mean a lost infantry platoon. This same accuracy is required by artillery fire direction centers so that targets may be located, identified, and fired upon. One of the more dangerous jobs assigned to the combat engineers is the work of clearing enemy mines. In support of tactical operations by our troops, engineers keep the way open for military movement. A Viet Cong suspect captured by an engineer reconnaissance team is questioned about enemy mines in the area. Acting on information gained from the suspect, a mine detection team works the grassy borders near the highway and uncovers a deadly trap. Engineer demolition specialists take over the job of destroying the enemy mines and booby traps. Often, however, in dealing with enemy devices, the combat engineer does not have the advantage of being told where to look. He must look everywhere. There it is, 50 pounds of tree trunks studded with bamboo spikes. Finding a booby trap is one thing. Safely disarming it is another. The examination of the surrounding area must be done with great care. One booby trap may be guarded by others so that if the main one is discovered, the man who circle around to disarm it may run into secondary traps, more cunningly concealed. A false sense of security is a luxury no combat engineer can afford. In this case, no other traps turn up. The hanging mace with its contaminated spikes is released to swing harmlessly through space instead of into the chest of some patrolling infantryman. One less danger in an area where danger can be anywhere. For example, in some torn patch of jungle where our troops have caught the enemy and driven him back, the Viet Cong often leaves an incredible maze of underground fortifications and tunnels. The enemy has burrowed into the earth for concealment and a place to store his food and weapons. To the combat engineer falls the job of exploring and destroying these subterranean passageways, riddled with hidden pitfalls and booby traps. Men of the recon section often find the underground network reaches hundreds of yards in various directions. The whole thing must be carefully charted before it can be effectively destroyed. A demolitions team prepares explosive charges for each tunnel in the underground maze. The enemy must be denied the possibility of ever using them again. Crews set up charges to make absolutely sure that the entire complex will be destroyed. Sometimes the enemy finds that nature has saved him the trouble of digging. These hidden natural caves were pinpointed by a repatriated member of the Viet Cong. Several days after American troops have swept through the area, combat engineers are called in to search the caves and make certain no new enemy forces have taken refuge there. As with the tunnels, these rocky sanctuaries are to be eliminated by the engineer demolition men. Charges are carried deep into the mountains and the caves cease to exist. In remote areas, inaccessible except by helicopter, the skills of specially selected air mobile engineers are called on and it takes special know-how. For example, if a copter can't come low enough to land a sling load, it has to drop it. The engineers have to know how to pack equipment to survive the drop. In the hands of professionals, these same tools can open up a landing area for troops or supplies quickly, where the enemy least expects them to be. Sometimes there are special hazards. On a mission to clear a landing area in enemy territory, this team finds a welter of bare timber beneath them. B-52 bombing is left behind treacherous splintered free trunks. One slip here could mean serious injury, perhaps death. But the men are out of the hovering copter and down the trooper ladder with the needed tools in moments. Perhaps the likelihood of sniper fire inspires them to spend as little time on the exposed ladder as possible. Quickly they hack and saw through the tangle of branches, stumps and brush. At any time, Viet Cong could step out of the jungles around them. A scouting detail sweeps the surrounding area to ensure the work party isn't taken by surprise. The word has passed, the job done on time. And though in the scope of the overall operation, this may be only one small aspect. The success of a large-scale combat effort depends on the successful completion of a thousand coordinated efforts. Other times, the mission of air mobile engineer teams may take on the proportions of a major construction job. Moldozers and other heavy equipment may be flown into an inaccessible area piece by piece. Objective? Carve a full-scale landing field out of the raw earth and do it fast. In successfully completing their vital support mission, the combat engineers come up with some ingenious ideas. If necessity is the mother of invention, here is one of her offspring, a kind of instant airfield. When the bulldozers finish their initial work in the wilderness, the men of the engineer spread a T-17 membrane. The huge nylon covering has a heavy-duty plastic coating, tough and waterproof. It converts a raw dirt strip into an all-weather runway for heavy cargo aircraft. Installed in sections, the panels are bonded together by a special plastic fusing cement. To prevent wind and rain from getting under the strip, the edges are anchored, dug in and covered up. Yesterday it was an inaccessible wilderness. Today it is an airfield able to handle the kind of heavy air cargo traffic it takes to support a major ground operation. In a more permanent type of air strip installation, the engineers have come up with these interlocking aluminum panels. Light, easy to handle, they have non-skid surfaces and can support the massive cargo-carrying aircraft so vital to rapid transport of supplies throughout Vietnam. The amount of material required to maintain a large-scale military operation, the mountains of ammunition, food, equipment, consumed, used up or destroyed by enemy action, this is something hard to imagine, even when you're on the spot. The urgency of the need, however, requires no imagining. It is always there. The knowledge that another air strip completed, another supply hub made operational, means that the people who need those supplies and need them on time will not be left without the necessities of combat, no matter where they are. It is this knowledge, this sense of urgency that quickens the working tempo of many an Army engineer as he goes about his mission, his multiple and vital mission in support of the Army's fighting forces in Vietnam. The role of the combat engineer in Vietnam is as varied and as challenging as the terrain. Sometimes modern technology plays a major part in his mission. Sometimes the accent is on plain hard work. A base camp in a heavy combat area calls for defenses that will protect against whatever comes. Bunkers to house machine gunners and riflemen are made by methods familiar to the Indian fighters of the American West. Notched logs cut from the surrounding forest that will fit together and stay put, but this must stand off more than arrows and tomahawks. The whole structure will be bulwarked with earth, and when roofed over and piled up with sandbags, these basically simple defenses can withstand even mortar and grenade attacks. You might not think that in this land of abundant water, drinking water would be a problem. But the innocent looking waters of Vietnam's rivers, deltas and waterways can kill as surely as a Viet Cong bullets. In the undeveloped outcountry where jungle warfare is waged, the combat engineers established water points. Here, through chemical treatment, they convert impure water to clear, safe drinking water. Our troops need a lot of it. From distant encampments, the water trucks come and tank up with fresh, pure water. The big bands used by the engineers for the water purification process have an amazing capacity for their size. They turn out more than four million gallons of pure water a month. The raw water, which is a carrier of a murderous variety of fevers, including typhoid, is first drawn through filters, then pumped into a mixing tank. Exact amounts of purification chemicals are mixed into it, killing all bacteria in the water. In the final stage, a special filtering system removes chemical traces and impurities. The result is water that is safe for human consumption. The climate in Vietnam is hot, humid and tough enough in itself. Without an abundance of clear, clean drinking water, the American soldier could not function. The combat engineers make sure that he has all he needs. The primary mission of the United States Army in Vietnam is to defeat the enemy in ground combat. The mission of the Army's combat engineers is to provide professional engineering support for that effort. The men of the combat engineers are fulfilling their supporting role. With every means at their command, the men of this vital action arm of the service are helping to keep America's fighting men in Vietnam moving. Despite every obstacle of nature and enemy action in this ancient land, the combat engineers of the United States Army continue to do their job. They clear the way.