Pakistan's madrassas: What you need to know
Pakistan has about 17,000 religious schools, or madrassas, which provide children with free religious education.
This means they have to memorise the Koran from as young as five-years-old.
There are nearly 2m students enrolled in Paksitan's madrassas.
But a 9/11 commission report in the US dubbed them as as "incubators for violent extremism".
BBC Urdu's Asif Farooq explains the increase in their popularity.