"Yoga" means union, merge. It is the unification of physical, mental and spiritual needs of each person. Thus we can see it as a mix between method, means and purpose. To reach a stable state, you must know your body, your reactions ... No question here about guru, yoga is not a sect or a believe. Yoga requires generally simple postures ie by holding the breath, the stillness, through concentration and relaxation. It provides overall suppleness, improved organ function and stronger immune system.
Yes, but where?
Iyengar or Hatha Yoga develops psychological and body faculties. (Sasasa Schaerbeek and Sasasa Uccle ) Some places also teach it in English or German. (Mahamudrayoga) But yoga is not only a relaxing discipline. It brings peace desired by everyone. (Dhyana)
Some people such as mothers need calm for their baby. (Clair de Lune) Many teachers of various courses are part of Iyengar Yoga association. All this is brought together in classes, seminars or books that are accessible at Ashtanga Yoga Institute or at Yogashram Center .