Gayatri Mantra tells you the way of life and is great for meditation. It is ultimate stress reliever and gives you calmess. it is universal prayer as the divine power is omnipresent with different names. One can perform yoga and meditation session with this. Gives a sound sleep when one listen before sleep. The divine meaning is explained below.

Gayatri Mantra - A Universal Prayer
Om Bhur Bhuvaḥ Swaḥ
Tat-savitur Vareñyaṃ
Bhargo Devasya Dheemahi
Dhiyo Yonaḥ Prachodayāt

General meaning: We meditate on that most adored Supreme Lord, the creator, whose effulgence (divine light) illumines all realms (physical, mental and spiritual). May this divine light illumine our intellect.

Word meaning: Om: The primeval sound; Bhur: the physical body/physical realm; Bhuvah: the life force/the mental realm Suvah: the soul/spiritual realm; Tat: That (God); Savitur: the Sun, Creator (source of all life); Vareñyam: adore; Bhargo: effulgence (divine light); Devasya: supreme Lord; Dhīmahi: meditate; Dhiyo: the intellect; Yo: May this light; Nah: our; Prachodayāt: illumine/inspire.