Tora Bora and the surrounding Spin Ghar range had natural caverns formed by streams eating into the limestone,[1] that had later been expanded into a CIA-financed complex built for the Afghan mujahideen.

[3] In October and November 1980, during Operation "Shkval", this complex was taken by the "Kaskad" special forces unit of the USSR KGB, together with the 66th motorized rifle brigade of the 40th Army of the Soviet troops in Afghanistan.

[citation needed] The base at Tora Bora was developed as a CIA-financed complex built for the Mujahideen following the 1979 Soviet invasion of Afghanistan,[4] 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.

[6] 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.

[13] 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.

[16] In 2017, Tora Bora was attacked and captured by the Islamic State of Iraq and the Levant – Khorasan Province (ISIL-K),[17] though the Afghan National Army soon recaptured it.