To protect themselves from the air-strikes, ISIS has built about 40 underground tunnels in the Sinjar town, Iraq. The town was under the control of Islamic State since August last year. Finally, Kurdish Forces reclaimed the city by fighting against the ISIS Militants. The Kurdish Forces were shocked to find a network of tunnels with sleeping quarters and electricity facilities. These tunnels were spread over several hundred metres and they start & end from houses. US-made explosive materials, medicine and copies of Koran were also found here.
The tunnels were like a secret network all over the city. ISIS used the underground passage to store weapons and explosives, treating it like their military arsenal. All the tunnels are narrow but tall enough for an adult to stand and walk freely. ISIS has been digging tunnels all over Iraq and Syria to use them for various purposes. This has been the strategy of Islamic State even before US & Other Nations began air-strikes.