You’ve probably heard the advice to change up your commute now and then as a way to take your brain off of autopilot and give your synapses a little exercise. Here’s another activity that might feed your grey matter: try contemplating the symbolism embedded in the modes of transportation you use for your daily commute. Sound too abstract? Let us explain for a moment.

Psychologist Carl Jung developed the concept of archetypal symbols as part of his theory of the collective unconscious. He argued that all of us are connected in a psychic space that exists beyond individual consciousness, where we share a common language. That’s why, according to Jungian theory, references to rivers, hats, ravens, or wheat, for instance, have held strikingly similar connotations in artwork, literature, and dreams, across cultures and through time. So, too, have more recent inventions, like cars, bicycles, trains, and subways, say, Jungian interpreters.

To Jung, there is symbolism in all that is around us, and fortunately for us, the symbolism shared by common forms of transportation as well as hundreds of other objects, flora, and fauna, are catalogued in The Book of Symbols: Reflections on Archetypal Images (Taschen, 2010). The subway, for instance, is described in the book as the “mythic basement.” You may not look at subways this way consciously, but for your subconscious mind, the subway tunnels “bring to mind caverns, catacombs, and labyrinths”—a dive into the unknown.

The bicycle, on the other hand, offers the figurative and literal independence and self-reliance of a car without the fumes and burning of fuel. “In particular, the bicycle symbolically evokes a vehicle of psychic energy and progression (the bicycle doesn’t move in reverse) that is personal rather than collective, and under the command of the individual ego,” The Book of Symbols tells us. Want to know what your mode of transportation symbolizes? If you do, just take a look right here.