VICKSBURG, Miss. — Artillery rained from the sky, forcing Mary Loughborough deeper into her dark, damp hiding place as she turned to her diary:
"Terror stricken, we remained crouched in the cave, while shell after shell followed each other in quick succession."
The caves were becoming a necessity, she wrote, for protection from the American bombardment.
The words were not smuggled from Afghanistan, where soldiers are targeting caves in the hunt for Osama bin Laden. They came instead from a different time and a different conflict--the Civil War--when Americans sought protection in caves from other Americans.
Loughborough captured that subterranean struggle in her 1864 book "My Cave Life in Vicksburg."
During the siege of Vicksburg, a crucial and deadly Civil War battle, Union forces shelled the Mississippi River city for 47 days. The fall of Vicksburg on July 4, 1863, helped the North gain control of the strategic river.
At the start of the siege, some 2,500 residents still lived in Vicksburg, then a compact community on the bluffs high above the twisting Mississippi.
Terry Winschel, a historian at the Vicksburg National Military Park, said that although it's unknown how many caves there were, a majority of the population sought shelter in the man-made hillside shelters.
Some caves housed hundreds. Some were a block long. Some had 70 feet of dirt overhead. All were for civilian protection.
"They were hiding from shells from either side," said Gordon Cotton, a historian from Vicksburg. "Shells knew no names. These were not real smart bombs, but they were just as deadly."
Winschel points out that soldiers' use of caves is nothing new. The Japanese hid in caves during World War II, and British soldiers sought refuge from the German blitzkrieg in man-made caves--subway tunnels.
In any type of war, though, it's perfectly legitimate for soldiers or civilians to hide in caves, he said. Even Bin Laden.
"I would refer to his use of caves as cowardly, but I can't blame him. I would want to survive," Winschel said.
Although Vicksburg's caves were man-made, Afghanistan's are often natural--surrounded by layers of hard rock instead of soft soil.
Military strategist James Dunnigan--author of several books, including "How to Make War"--says that caves are now less attractive because of military advances. Tear gas, satchel charges and fuel-air explosives--which burn up and suffocate people by using up all the oxygen--make caves less secure than 140 years ago.
In Afghanistan, myriad caves make for easy hiding. It was the same in Vicksburg.
"Caves were the fashion--the rage--over besieged Vicksburg," Loughborough wrote. "Negroes, who understood their business, hired themselves out to dig them."
At least one of Vicksburg's caves still survives, though it's mostly collapsed and overgrown. Gordon and Winschel each crawled through the Huff family cave in the 1980s. A bench that was carved in the dirt wall and used as a bed had not yet eroded.
The caves worked. Civilian fatalities were kept to a minimum, Winschel said. Targeted Afghanistan caves likely won't provide the same safety.
"Whereas the U.S. Army in 1863 had no specific method for adversaries hiding in caves, we certainly have weaponry today that can do the trick," Winschel said. "Someone said Bin Laden should pick out his favorite cave, because it might be his final resting place."