Hooks pierce the back of an ethnic Tamil man as he performs the Vel Kavadi ritual during the annual Thaipusam festival of penance and thanksgiving. The practice involves dragging a portable altar by a set of hooks that pierce the back, a form of mortification which follows a session of fasting and prayer. The devotees in a trance rarely shed any blood or remember feeling any pain afterwards. The Tamil Hindu festival commemorates the birth of Hindu Lord Murugan and his triumph over evil. Pilgrims engage in various acts of devotion such as carrying burdens, flagellation and body piercing as they take part in a 15-kilometre procession to the Batu Caves. .