The lithological nature of Tora Bora is predominantly metamorphic gneiss and schist.
Military base
The base at Tora Bora was developed as a CIA-financed complex built for the Mujahideen following the 1979 Soviet invasion of Afghanistan, and has been described by the western media as an "impregnable cave fortress" housing 2,000 men complete with a hospital, a hydroelectric power plant, offices, a hotel, arms and ammunition stores, roads large enough to drive a tank into, and sophisticated tunnel, and ventilation systems. During the U.S. invasion of Afghanistan, the cave complex was one of the strongholds of the Taliban and Al-Qaeda, according to United States Secretary of DefenseDonald Rumsfeld. It was the location of the December 2001Battle of Tora Bora, and suspected hideout of Al-Qaeda leader Osama bin Laden. It was reported that in 2007, U.S. intelligence suspected bin Laden planned to meet with top Al-Qaeda and Taliban commanders at Tora Bora prior to the launch of a possible attack on Europe or the United States. Both the British and American press published detailed plans of the base. When shown a plan during an NBC interview, Rumsfeld said, "This is serious business; there's not one of those, there are many of those". An elaborate military operation was planned which included deployment of the CIA-US Special Operations Forces team with laser markers to guide non-stop heavy air strikes during 72 hours. When Tora Bora was eventually captured by the U.S. and Afghan troops, no traces of the supposed "fortress" were found despite painstaking searches in the surrounding areas. Tora Bora turned out to be a system of small natural caves housing, at most, 200 fighters. While arms and ammunition stores were found, there were no traces of the advanced facilities claimed to exist. In a 2002 interview with by PBS's Frontline, a Staff Sergeant from the U.S. Special Forces Operational Detachment Alpha 572 described the caves: The complex later was retaken by the Taliban, and served as an important base for the Taliban insurgency. In 2017, Tora Bora was attacked and captured by the Islamic State of Iraq and the Levant – Khorasan Province, though the Afghan National Army soon recaptured it.