The Nautilus shell is probably the most well known spiral symbol we can think of. Over 500 million years old they are amazing examples of sacred geometry. As the body of the Nautilus grows it moves from one chamber to the next within its shell sealing the old behind it. A shell can have as many as 30 chambers within it. Each spiral of the Nautilus shell grows larger by Phi (the Golden Ratio that is the building block of the universe). Each revolution is the completion of a cycle.
Sacred Geometry is a reflection of the universe and the dynamic inter-connectedness between ourselves and the natural world. The spiral is a common element in sacred Geometry. It can be found in the symbolism of numerous cultures throughout the world. Much like archetypal figures it is a universal symbol that finds its way into cultures everywhere. They appeal to us on a core/base level. There is something appealing about the elegance and beauty of the spiral that we all feel connected to.
The Spiral represents a journey, the movement through stages (much as the nautilus moves from chamber to chamber) in your life in order to grow and continue your cycle. The spiral is life's journey - it is found in nature, in the universe, in our DNA. It is also a highly useful tool for meditation. For myself, when I want to take a dedicated journey in a meditative state - I visualize myself spiraling down a set of stairs into my deep conscious in order to access that part of myself. Another meditative technique is to visualize a spiral (or actually print one out) where you can begin at the center and work your way up through the spiral, pausing, reflecting, taking the time to appreciate the changes that take place with each turn, taking time to look back and view the spiral you have just walked. Its a great way to view your journey so far, as well as what may lay ahead.