Just as the name sounds, the crown chakra (Sahasrara) is located at the top and center of your head and is where your higher consciousness and central nervous system meet. The crown chakra is believed to be closely related to our spiritual journeys and Samadhi (enlightenment), the final limb of the 8 limbs of yoga.
Sahasrara means a thousand petals in Sanskrit, giving the visual of a thousand petals of the lotus flowers being arranged on top of one another in a mandala shape. In several eastern traditions, the lotus flower signifies purity and rebirth.
Enlightenment is a journey that in yoga, requires disciplined devotion to Ashtanga, the 8 limbs of yoga. While utilizing yoga medicine for the crown chakra will certainly not bring ultimate feelings of unity with the universe - it can allow for spiritual blocks to be shifted and even for feelings of bliss to arise.
Balancing this chakra relates to being present and feeling connected to the Divine. In your spiritual practice, the divine can mean different things - maybe God or higher consciousness. You may adapt this visual to what it means to you in your belief system.