How many caves are there?


Thousands. Afghanistan’s rugged terrain is honeycombed with natural caverns and man-made tunnels. The Hindu Kush mountains are pocked with caves scooped out of limestone by melting snow. In the sandstone foothills of the southeastern part of the country, everyone from warriors to farmers has carved tunnels that provide ideal hiding places for fighters and ammunition. The hideouts also include caves dug deep into the granite bedrock during the war with the Soviets in the 1980s. This underground warren is connected by

crisscrossing passageways, and is equipped with escape tunnels. Some of these massive caves are large enough to drive a truck into, or to house a few tanks and a fighter jet.

Can’t U.S. warplanes

just bomb the caves?


They have already begun to. Bombardiers last week began zeroing in on caves, trying to blast their openings to seal them off. But bin Laden and his men are probably not hiding in the largest caverns, said Milt Bearden, a former CIA agent who operated in Afghanistan during the Soviet invasion. Al Qaida favors smaller, man-made shelters dug into the sides of mountains, typically no more than 30 feet deep. Some are little more than personal foxholes. These small bunkers would be vulnerable to a direct hit, but scoring a bull’s-eye won’t be easy. “You have to drop bombs down sheer walls and rock faces,” Bearden told The Dallas Morning News. “Most were built to be safe from any air or missile attack.”

What are the bunkers like inside?


Spare, but equipped with all the essentials. Journalists who visited bin Laden in a cave outside Kandahar said it had three rooms. One had several laptop and desktop computers, two fax machines, and a satellite telephone. Another was used as a small weapons depot. The third room had three beds and a library of classic Islamic writings. The land is peppered with these command centers, each specially fortified with steel. CIA agents stationed in Pakistan call them “bat caves.” They were built during the war with the Soviets (1979-89) as command bunkers for Afghan resistance fighters. Bin Laden, an engineer and millionaire heir to a Saudi construction fortune, built some of them himself. Others were financed with the help of the CIA, which provided aid to the mujaheddin.

Can bombs destroy the caves?


In some cases, yes. Military engineers have designed weapons, nicknamed “bunker busters,“ to penetrate rock and detonate underground. They were invented during the Gulf War to destroy Saddam Hussein’s command bunkers. To penetrate those bunkers, the engineers packed explosives into the 8-inch-wide barrels of surplus howitzers and attached them to laser-guided electronics. The result was a 5,000-pound, laser-guided bomb designed to smash through 100 feet of earth or up to 30 feet of reinforced concrete before detonating. But a former mujaheddin fighter told USA Today that some of the caves are buried so deep in the granite mountains that bombing them is useless. He said that when the Soviets bombed these hideouts, “we wouldn’t even know it because we were down so deep. We weren’t even afraid of an atom bomb.”

What about the tunnels?


Most of them were built for irrigation centuries ago. Afghanistan’s populated plains have a very arid climate, and rivers dry up for months at a time. Farmers built the first tunnels, called karez, to transport water from the mountains to their crops. The tunnels typically begin at the foot of mountainous areas, where the initial well is dug down to the water table. The channels then follow a gentle slope to the population centers they support. Some historians believe the underground irrigation system was already in place when Alexander the Great conquered present-day Afghanistan on his way to India in 328 B.C.

How big are they?


Some of the tunnels burrow 100 feet into the earth, and snake along for more than a mile. Their paths are marked by mounds of earth around ventilation shafts that are dug every 100 to 200 feet; for that reason, pilots can easily spot the tunnels from the air.

Have the tunnels been used in past wars?


Yes, Afghan soldiers have been hiding in them since they battled Genghis Khan in the 13th century. Rather than chase Afghans into the tunnels, the Mongols staked out the exits with small patrols and pounced on people when they emerged. The Soviets, in the 1980s, weren’t as patient. When they discovered that the mujaheddin were hiding in specific tunnels, the Soviets dropped grenades or incendiary devices into the shafts and killed many Afghan fighters.

Will the hunt stop in winter?


The first snows might slow down the overall military assault, but will make it easier to hunt down bin Laden. With thermal-guided cameras on low-flying helicopters, the U.S. will be able to pinpoint any fires or other heat sources bin Laden and his cohorts use to stay warm-even if those fires are underground. Once a heat source is found, U.S. commanders could blast the hideouts with AGM-130 missiles, which are designed to fly horizontally and can therefore fly directly into the mouth of a cave.

A game of cat and mouse


The U.S. military is narrowing down the search for its enemies in Afghanistan to several “kill zones,” including towns where they could blend in with civilians and intricate cave complexes in Taliban strongholds. The center of the search is a network of caves in the Paktia and Paktika provinces in the southeast, bordering Pakistan. Russian intelligence services were the first to alert the U.S. to the existence of these complexes. Special Forces soldiers on the ground, spy planes and satellites, and defectors are pointing U.S. bombers to specific regions and even to specific caves. “We have a better knowledge now of where these caves are and who or what is inside of them,” a senior military official told The New York Times. As the hunt continues, military chiefs are debating whether to continue the attack from the air, or send in commandos. Many of the caves are protected by minefields, and their entrances are booby-trapped.