Kriya Yoga

Kriya Yoga is a yoga system that was made public again in the 19th century by Mahavatar Goraksha Babaji and his disciple Lahiri Mahasaya. The practice relies on various levels of breathing techniques, mantras and mudras (body postures) to speed up the process of spiritual development, cleanse the energetic system, and awaken Kundalini Shakti.
For a long time, these techniques were only handed down in the Guru-Disciple tradition of the Siddha Nath Yogis.
There are descriptions of the Kriya Yoga practices already in the Bhagavad Gita and in the Yoga Sutras of Patanjali, where they are in highest esteem.